diff --git a/.travis.yml b/.travis.yml
index b2cc7b02b..ecb31ef0f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,13 @@
 # - A travis bug causes caches to trample eachother when using the same
 #   compiler key (which we don't use anyway). This is worked around for now by
 #   replacing the "compilers" with a build name prefixed by the no-op ":"
-#   command. See: https://github.com/travis-ci/casher/issues/6
+#   command. See: https://github.com/travis-ci/travis-ci/issues/4393
+# - sudo/dist/group are set so as to get Blue Box VMs, necessary for [loopback]
+#   IPv6 support
+
+sudo: required
+dist: precise
+group: legacy
 
 os: linux
 language: cpp
@@ -51,7 +57,7 @@ install:
 before_script:
     - unset CC; unset CXX
     - mkdir -p depends/SDKs depends/sdk-sources
-    - if [ -n "$OSX_SDK" -a ! -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then wget $SDK_URL/MacOSX${OSX_SDK}.sdk.tar.gz -O depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
+    - if [ -n "$OSX_SDK" -a ! -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then curl --location --fail $SDK_URL/MacOSX${OSX_SDK}.sdk.tar.gz -o depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - if [ -n "$OSX_SDK" -a -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then tar -C depends/SDKs -xf depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - make $MAKEJOBS -C depends HOST=$HOST $DEP_OPTS
 script:
diff --git a/build-aux/m4/ax_boost_base.m4 b/build-aux/m4/ax_boost_base.m4
index 3f24d5ddc..45d948933 100644
--- a/build-aux/m4/ax_boost_base.m4
+++ b/build-aux/m4/ax_boost_base.m4
@@ -33,7 +33,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 23
+#serial 26
 
 AC_DEFUN([AX_BOOST_BASE],
 [
@@ -95,8 +95,8 @@ if test "x$want_boost" = "xyes"; then
       x86_64)
         libsubdirs="lib64 libx32 lib lib64"
         ;;
-      ppc64|s390x|sparc64|aarch64)
-        libsubdirs="lib64 lib lib64"
+      ppc64|s390x|sparc64|aarch64|ppc64le)
+        libsubdirs="lib64 lib lib64 ppc64le"
         ;;
     esac
 
@@ -170,7 +170,7 @@ if test "x$want_boost" = "xyes"; then
         AC_MSG_RESULT(yes)
     succeeded=yes
     found_system=yes
-        ],[:
+        ],[
         ])
     AC_LANG_POP([C++])
 
@@ -179,6 +179,10 @@ if test "x$want_boost" = "xyes"; then
     dnl if we found no boost with system layout we search for boost libraries
     dnl built and installed without the --layout=system option or for a staged(not installed) version
     if test "x$succeeded" != "xyes"; then
+        CPPFLAGS="$CPPFLAGS_SAVED"
+        LDFLAGS="$LDFLAGS_SAVED"
+        BOOST_CPPFLAGS=
+        BOOST_LDFLAGS=
         _version=0
         if test "$ac_boost_path" != ""; then
             if test -d "$ac_boost_path" && test -r "$ac_boost_path"; then
@@ -191,6 +195,12 @@ if test "x$want_boost" = "xyes"; then
                     VERSION_UNDERSCORE=`echo $_version | sed 's/\./_/'`
                     BOOST_CPPFLAGS="-I$ac_boost_path/include/boost-$VERSION_UNDERSCORE"
                 done
+                dnl if nothing found search for layout used in Windows distributions
+                if test -z "$BOOST_CPPFLAGS"; then
+                    if test -d "$ac_boost_path/boost" && test -r "$ac_boost_path/boost"; then
+                        BOOST_CPPFLAGS="-I$ac_boost_path"
+                    fi
+                fi
             fi
         else
             if test "$cross_compiling" != yes; then
@@ -253,7 +263,7 @@ if test "x$want_boost" = "xyes"; then
             AC_MSG_RESULT(yes)
         succeeded=yes
         found_system=yes
-            ],[:
+            ],[
             ])
         AC_LANG_POP([C++])
     fi
diff --git a/build-aux/m4/ax_boost_program_options.m4 b/build-aux/m4/ax_boost_program_options.m4
index f59144185..2bdb59371 100644
--- a/build-aux/m4/ax_boost_program_options.m4
+++ b/build-aux/m4/ax_boost_program_options.m4
@@ -29,7 +29,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 22
+#serial 24
 
 AC_DEFUN([AX_BOOST_PROGRAM_OPTIONS],
 [
@@ -63,9 +63,9 @@ AC_DEFUN([AX_BOOST_PROGRAM_OPTIONS],
 		AC_CACHE_CHECK([whether the Boost::Program_Options library is available],
 					   ax_cv_boost_program_options,
 					   [AC_LANG_PUSH(C++)
-				AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <boost/program_options.hpp>
+				AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <boost/program_options/errors.hpp>
                                                           ]],
-                                  [[boost::program_options::options_description generic("Generic options");
+                                  [[boost::program_options::error err("Error message");
                                    return 0;]])],
                            ax_cv_boost_program_options=yes, ax_cv_boost_program_options=no)
 					AC_LANG_POP([C++])
@@ -74,7 +74,6 @@ AC_DEFUN([AX_BOOST_PROGRAM_OPTIONS],
 				AC_DEFINE(HAVE_BOOST_PROGRAM_OPTIONS,,[define if the Boost::PROGRAM_OPTIONS library is available])
                   BOOSTLIBDIR=`echo $BOOST_LDFLAGS | sed -e 's/@<:@^\/@:>@*//'`
                 if test "x$ax_boost_user_program_options_lib" = "x"; then
-                ax_lib=
                 for libextension in `ls $BOOSTLIBDIR/libboost_program_options*.so* 2>/dev/null | sed 's,.*/,,' | sed -e 's;^lib\(boost_program_options.*\)\.so.*$;\1;'` `ls $BOOSTLIBDIR/libboost_program_options*.dylib* 2>/dev/null | sed 's,.*/,,' | sed -e 's;^lib\(boost_program_options.*\)\.dylib.*$;\1;'` `ls $BOOSTLIBDIR/libboost_program_options*.a* 2>/dev/null | sed 's,.*/,,' | sed -e 's;^lib\(boost_program_options.*\)\.a.*$;\1;'` ; do
                      ax_lib=${libextension}
 				    AC_CHECK_LIB($ax_lib, exit,
diff --git a/build-aux/m4/ax_boost_system.m4 b/build-aux/m4/ax_boost_system.m4
index 9c78280fc..1c05450cb 100644
--- a/build-aux/m4/ax_boost_system.m4
+++ b/build-aux/m4/ax_boost_system.m4
@@ -31,7 +31,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 17
+#serial 18
 
 AC_DEFUN([AX_BOOST_SYSTEM],
 [
@@ -68,9 +68,10 @@ AC_DEFUN([AX_BOOST_SYSTEM],
 					   ax_cv_boost_system,
         [AC_LANG_PUSH([C++])
 			 CXXFLAGS_SAVE=$CXXFLAGS
+			 CXXFLAGS=
 
 			 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <boost/system/error_code.hpp>]],
-                                   [[boost::system::system_category]])],
+				    [[boost::system::error_category *a = 0;]])],
                    ax_cv_boost_system=yes, ax_cv_boost_system=no)
 			 CXXFLAGS=$CXXFLAGS_SAVE
              AC_LANG_POP([C++])
diff --git a/build-aux/m4/ax_check_compile_flag.m4 b/build-aux/m4/ax_check_compile_flag.m4
index c3a8d695a..ca3639715 100644
--- a/build-aux/m4/ax_check_compile_flag.m4
+++ b/build-aux/m4/ax_check_compile_flag.m4
@@ -4,7 +4,7 @@
 #
 # SYNOPSIS
 #
-#   AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS])
+#   AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
 #
 # DESCRIPTION
 #
@@ -19,6 +19,8 @@
 #   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
 #   force the compiler to issue an error when a bad flag is given.
 #
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
 #   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
 #   macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
 #
@@ -53,19 +55,19 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 2
+#serial 4
 
 AC_DEFUN([AX_CHECK_COMPILE_FLAG],
-[AC_PREREQ(2.59)dnl for _AC_LANG_PREFIX
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
 AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
 AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
   ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
   _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
+  AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
     [AS_VAR_SET(CACHEVAR,[yes])],
     [AS_VAR_SET(CACHEVAR,[no])])
   _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
-AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes],
+AS_VAR_IF(CACHEVAR,yes,
   [m4_default([$2], :)],
   [m4_default([$3], :)])
 AS_VAR_POPDEF([CACHEVAR])dnl
diff --git a/build-aux/m4/ax_check_link_flag.m4 b/build-aux/m4/ax_check_link_flag.m4
index e2d0d363e..eb01a6ce1 100644
--- a/build-aux/m4/ax_check_link_flag.m4
+++ b/build-aux/m4/ax_check_link_flag.m4
@@ -4,7 +4,7 @@
 #
 # SYNOPSIS
 #
-#   AX_CHECK_LINK_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS])
+#   AX_CHECK_LINK_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
 #
 # DESCRIPTION
 #
@@ -19,6 +19,8 @@
 #   EXTRA-FLAGS FLAG".  This can for example be used to force the linker to
 #   issue an error when a bad flag is given.
 #
+#   INPUT gives an alternative input source to AC_LINK_IFELSE.
+#
 #   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
 #   macro in sync with AX_CHECK_{PREPROC,COMPILE}_FLAG.
 #
@@ -53,18 +55,19 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 2
+#serial 4
 
 AC_DEFUN([AX_CHECK_LINK_FLAG],
-[AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_ldflags_$4_$1])dnl
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_ldflags_$4_$1])dnl
 AC_CACHE_CHECK([whether the linker accepts $1], CACHEVAR, [
   ax_check_save_flags=$LDFLAGS
   LDFLAGS="$LDFLAGS $4 $1"
-  AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+  AC_LINK_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
     [AS_VAR_SET(CACHEVAR,[yes])],
     [AS_VAR_SET(CACHEVAR,[no])])
   LDFLAGS=$ax_check_save_flags])
-AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes],
+AS_VAR_IF(CACHEVAR,yes,
   [m4_default([$2], :)],
   [m4_default([$3], :)])
 AS_VAR_POPDEF([CACHEVAR])dnl
diff --git a/build-aux/m4/ax_check_preproc_flag.m4 b/build-aux/m4/ax_check_preproc_flag.m4
index b1cfef6b8..ca1d5ee2b 100644
--- a/build-aux/m4/ax_check_preproc_flag.m4
+++ b/build-aux/m4/ax_check_preproc_flag.m4
@@ -4,7 +4,7 @@
 #
 # SYNOPSIS
 #
-#   AX_CHECK_PREPROC_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS])
+#   AX_CHECK_PREPROC_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
 #
 # DESCRIPTION
 #
@@ -19,6 +19,8 @@
 #   "CPPFLAGS EXTRA-FLAGS FLAG".  This can for example be used to force the
 #   preprocessor to issue an error when a bad flag is given.
 #
+#   INPUT gives an alternative input source to AC_PREPROC_IFELSE.
+#
 #   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
 #   macro in sync with AX_CHECK_{COMPILE,LINK}_FLAG.
 #
@@ -53,19 +55,19 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 2
+#serial 4
 
 AC_DEFUN([AX_CHECK_PREPROC_FLAG],
-[AC_PREREQ(2.59)dnl for _AC_LANG_PREFIX
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
 AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]cppflags_$4_$1])dnl
 AC_CACHE_CHECK([whether _AC_LANG preprocessor accepts $1], CACHEVAR, [
   ax_check_save_flags=$CPPFLAGS
   CPPFLAGS="$CPPFLAGS $4 $1"
-  AC_PREPROC_IFELSE([AC_LANG_PROGRAM()],
+  AC_PREPROC_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
     [AS_VAR_SET(CACHEVAR,[yes])],
     [AS_VAR_SET(CACHEVAR,[no])])
   CPPFLAGS=$ax_check_save_flags])
-AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes],
+AS_VAR_IF(CACHEVAR,yes,
   [m4_default([$2], :)],
   [m4_default([$3], :)])
 AS_VAR_POPDEF([CACHEVAR])dnl
diff --git a/build-aux/m4/ax_cxx_compile_stdcxx.m4 b/build-aux/m4/ax_cxx_compile_stdcxx.m4
new file mode 100644
index 000000000..2c18e49c5
--- /dev/null
+++ b/build-aux/m4/ax_cxx_compile_stdcxx.m4
@@ -0,0 +1,562 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
+#
+# DESCRIPTION
+#
+#   Check for baseline language coverage in the compiler for the specified
+#   version of the C++ standard.  If necessary, add switches to CXX and
+#   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard)
+#   or '14' (for the C++14 standard).
+#
+#   The second argument, if specified, indicates whether you insist on an
+#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
+#   -std=c++11).  If neither is specified, you get whatever works, with
+#   preference for an extended mode.
+#
+#   The third argument, if specified 'mandatory' or if left unspecified,
+#   indicates that baseline support for the specified C++ standard is
+#   required and that the macro should error out if no mode with that
+#   support is found.  If specified 'optional', then configuration proceeds
+#   regardless, after defining HAVE_CXX${VERSION} if and only if a
+#   supporting mode is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
+#   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
+#   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
+#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
+#   Copyright (c) 2015 Paul Norman <penorman@mac.com>
+#   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.  This file is offered as-is, without any
+#   warranty.
+
+#serial 4
+
+dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
+dnl  (serial version number 13).
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
+  m4_if([$1], [11], [],
+        [$1], [14], [],
+        [$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])],
+        [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
+  m4_if([$2], [], [],
+        [$2], [ext], [],
+        [$2], [noext], [],
+        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
+  m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
+        [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
+        [$3], [optional], [ax_cxx_compile_cxx$1_required=false],
+        [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
+  AC_LANG_PUSH([C++])dnl
+  ac_success=no
+  AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+  ax_cv_cxx_compile_cxx$1,
+  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+    [ax_cv_cxx_compile_cxx$1=yes],
+    [ax_cv_cxx_compile_cxx$1=no])])
+  if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+    ac_success=yes
+  fi
+
+  m4_if([$2], [noext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=gnu++$1 -std=gnu++0x; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+                     $cachevar,
+        [ac_save_CXX="$CXX"
+         CXX="$CXX $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXX="$ac_save_CXX"])
+      if eval test x\$$cachevar = xyes; then
+        CXX="$CXX $switch"
+        if test -n "$CXXCPP" ; then
+          CXXCPP="$CXXCPP $switch"
+        fi
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+
+  m4_if([$2], [ext], [], [dnl
+  if test x$ac_success = xno; then
+    dnl HP's aCC needs +std=c++11 according to:
+    dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
+    dnl Cray's crayCC needs "-h std=c++11"
+    for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+                     $cachevar,
+        [ac_save_CXX="$CXX"
+         CXX="$CXX $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXX="$ac_save_CXX"])
+      if eval test x\$$cachevar = xyes; then
+        CXX="$CXX $switch"
+        if test -n "$CXXCPP" ; then
+          CXXCPP="$CXXCPP $switch"
+        fi
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+  AC_LANG_POP([C++])
+  if test x$ax_cxx_compile_cxx$1_required = xtrue; then
+    if test x$ac_success = xno; then
+      AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
+    fi
+  fi
+  if test x$ac_success = xno; then
+    HAVE_CXX$1=0
+    AC_MSG_NOTICE([No compiler with C++$1 support was found])
+  else
+    HAVE_CXX$1=1
+    AC_DEFINE(HAVE_CXX$1,1,
+              [define if the compiler supports basic C++$1 syntax])
+  fi
+  AC_SUBST(HAVE_CXX$1)
+])
+
+
+dnl  Test body for checking C++11 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+)
+
+
+dnl  Test body for checking C++14 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+)
+
+
+dnl  Tests for new features in C++11
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+  namespace test_static_assert
+  {
+
+    template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+  }
+
+  namespace test_final_override
+  {
+
+    struct Base
+    {
+      virtual void f() {}
+    };
+
+    struct Derived : public Base
+    {
+      virtual void f() override {}
+    };
+
+  }
+
+  namespace test_double_right_angle_brackets
+  {
+
+    template < typename T >
+    struct check {};
+
+    typedef check<void> single_type;
+    typedef check<check<void>> double_type;
+    typedef check<check<check<void>>> triple_type;
+    typedef check<check<check<check<void>>>> quadruple_type;
+
+  }
+
+  namespace test_decltype
+  {
+
+    int
+    f()
+    {
+      int a = 1;
+      decltype(a) b = 2;
+      return a + b;
+    }
+
+  }
+
+  namespace test_type_deduction
+  {
+
+    template < typename T1, typename T2 >
+    struct is_same
+    {
+      static const bool value = false;
+    };
+
+    template < typename T >
+    struct is_same<T, T>
+    {
+      static const bool value = true;
+    };
+
+    template < typename T1, typename T2 >
+    auto
+    add(T1 a1, T2 a2) -> decltype(a1 + a2)
+    {
+      return a1 + a2;
+    }
+
+    int
+    test(const int c, volatile int v)
+    {
+      static_assert(is_same<int, decltype(0)>::value == true, "");
+      static_assert(is_same<int, decltype(c)>::value == false, "");
+      static_assert(is_same<int, decltype(v)>::value == false, "");
+      auto ac = c;
+      auto av = v;
+      auto sumi = ac + av + 'x';
+      auto sumf = ac + av + 1.0;
+      static_assert(is_same<int, decltype(ac)>::value == true, "");
+      static_assert(is_same<int, decltype(av)>::value == true, "");
+      static_assert(is_same<int, decltype(sumi)>::value == true, "");
+      static_assert(is_same<int, decltype(sumf)>::value == false, "");
+      static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+      return (sumf > 0.0) ? sumi : add(c, v);
+    }
+
+  }
+
+  namespace test_noexcept
+  {
+
+    int f() { return 0; }
+    int g() noexcept { return 0; }
+
+    static_assert(noexcept(f()) == false, "");
+    static_assert(noexcept(g()) == true, "");
+
+  }
+
+  namespace test_constexpr
+  {
+
+    template < typename CharT >
+    unsigned long constexpr
+    strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+    {
+      return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+    }
+
+    template < typename CharT >
+    unsigned long constexpr
+    strlen_c(const CharT *const s) noexcept
+    {
+      return strlen_c_r(s, 0UL);
+    }
+
+    static_assert(strlen_c("") == 0UL, "");
+    static_assert(strlen_c("1") == 1UL, "");
+    static_assert(strlen_c("example") == 7UL, "");
+    static_assert(strlen_c("another\0example") == 7UL, "");
+
+  }
+
+  namespace test_rvalue_references
+  {
+
+    template < int N >
+    struct answer
+    {
+      static constexpr int value = N;
+    };
+
+    answer<1> f(int&)       { return answer<1>(); }
+    answer<2> f(const int&) { return answer<2>(); }
+    answer<3> f(int&&)      { return answer<3>(); }
+
+    void
+    test()
+    {
+      int i = 0;
+      const int c = 0;
+      static_assert(decltype(f(i))::value == 1, "");
+      static_assert(decltype(f(c))::value == 2, "");
+      static_assert(decltype(f(0))::value == 3, "");
+    }
+
+  }
+
+  namespace test_uniform_initialization
+  {
+
+    struct test
+    {
+      static const int zero {};
+      static const int one {1};
+    };
+
+    static_assert(test::zero == 0, "");
+    static_assert(test::one == 1, "");
+
+  }
+
+  namespace test_lambdas
+  {
+
+    void
+    test1()
+    {
+      auto lambda1 = [](){};
+      auto lambda2 = lambda1;
+      lambda1();
+      lambda2();
+    }
+
+    int
+    test2()
+    {
+      auto a = [](int i, int j){ return i + j; }(1, 2);
+      auto b = []() -> int { return '0'; }();
+      auto c = [=](){ return a + b; }();
+      auto d = [&](){ return c; }();
+      auto e = [a, &b](int x) mutable {
+        const auto identity = [](int y){ return y; };
+        for (auto i = 0; i < a; ++i)
+          a += b--;
+        return x + identity(a + b);
+      }(0);
+      return a + b + c + d + e;
+    }
+
+    int
+    test3()
+    {
+      const auto nullary = [](){ return 0; };
+      const auto unary = [](int x){ return x; };
+      using nullary_t = decltype(nullary);
+      using unary_t = decltype(unary);
+      const auto higher1st = [](nullary_t f){ return f(); };
+      const auto higher2nd = [unary](nullary_t f1){
+        return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+      };
+      return higher1st(nullary) + higher2nd(nullary)(unary);
+    }
+
+  }
+
+  namespace test_variadic_templates
+  {
+
+    template <int...>
+    struct sum;
+
+    template <int N0, int... N1toN>
+    struct sum<N0, N1toN...>
+    {
+      static constexpr auto value = N0 + sum<N1toN...>::value;
+    };
+
+    template <>
+    struct sum<>
+    {
+      static constexpr auto value = 0;
+    };
+
+    static_assert(sum<>::value == 0, "");
+    static_assert(sum<1>::value == 1, "");
+    static_assert(sum<23>::value == 23, "");
+    static_assert(sum<1, 2>::value == 3, "");
+    static_assert(sum<5, 5, 11>::value == 21, "");
+    static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+  }
+
+  // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+  // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+  // because of this.
+  namespace test_template_alias_sfinae
+  {
+
+    struct foo {};
+
+    template<typename T>
+    using member = typename T::member_type;
+
+    template<typename T>
+    void func(...) {}
+
+    template<typename T>
+    void func(member<T>*) {}
+
+    void test();
+
+    void test() { func<foo>(0); }
+
+  }
+
+}  // namespace cxx11
+
+#endif  // __cplusplus >= 201103L
+
+]])
+
+
+dnl  Tests for new features in C++14
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
+
+// If the compiler admits that it is not ready for C++14, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201402L
+
+#error "This is not a C++14 compiler"
+
+#else
+
+namespace cxx14
+{
+
+  namespace test_polymorphic_lambdas
+  {
+
+    int
+    test()
+    {
+      const auto lambda = [](auto&&... args){
+        const auto istiny = [](auto x){
+          return (sizeof(x) == 1UL) ? 1 : 0;
+        };
+        const int aretiny[] = { istiny(args)... };
+        return aretiny[0];
+      };
+      return lambda(1, 1L, 1.0f, '1');
+    }
+
+  }
+
+  namespace test_binary_literals
+  {
+
+    constexpr auto ivii = 0b0000000000101010;
+    static_assert(ivii == 42, "wrong value");
+
+  }
+
+  namespace test_generalized_constexpr
+  {
+
+    template < typename CharT >
+    constexpr unsigned long
+    strlen_c(const CharT *const s) noexcept
+    {
+      auto length = 0UL;
+      for (auto p = s; *p; ++p)
+        ++length;
+      return length;
+    }
+
+    static_assert(strlen_c("") == 0UL, "");
+    static_assert(strlen_c("x") == 1UL, "");
+    static_assert(strlen_c("test") == 4UL, "");
+    static_assert(strlen_c("another\0test") == 7UL, "");
+
+  }
+
+  namespace test_lambda_init_capture
+  {
+
+    int
+    test()
+    {
+      auto x = 0;
+      const auto lambda1 = [a = x](int b){ return a + b; };
+      const auto lambda2 = [a = lambda1(x)](){ return a; };
+      return lambda2();
+    }
+
+  }
+
+  namespace test_digit_seperators
+  {
+
+    constexpr auto ten_million = 100'000'000;
+    static_assert(ten_million == 100000000, "");
+
+  }
+
+  namespace test_return_type_deduction
+  {
+
+    auto f(int& x) { return x; }
+    decltype(auto) g(int& x) { return x; }
+
+    template < typename T1, typename T2 >
+    struct is_same
+    {
+      static constexpr auto value = false;
+    };
+
+    template < typename T >
+    struct is_same<T, T>
+    {
+      static constexpr auto value = true;
+    };
+
+    int
+    test()
+    {
+      auto x = 0;
+      static_assert(is_same<int, decltype(f(x))>::value, "");
+      static_assert(is_same<int&, decltype(g(x))>::value, "");
+      return x;
+    }
+
+  }
+
+}  // namespace cxx14
+
+#endif  // __cplusplus >= 201402L
+
+]])
diff --git a/build-aux/m4/ax_gcc_func_attribute.m4 b/build-aux/m4/ax_gcc_func_attribute.m4
index 275ca63a2..c788ca9bd 100644
--- a/build-aux/m4/ax_gcc_func_attribute.m4
+++ b/build-aux/m4/ax_gcc_func_attribute.m4
@@ -31,6 +31,7 @@
 #    cold
 #    const
 #    constructor
+#    constructor_priority for constructor attribute with priority
 #    deprecated
 #    destructor
 #    dllexport
@@ -73,7 +74,7 @@
 #   and this notice are preserved.  This file is offered as-is, without any
 #   warranty.
 
-#serial 2
+#serial 3
 
 AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
     AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1])
@@ -103,6 +104,9 @@ AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
                 [const], [
                     int foo( void ) __attribute__(($1));
                 ],
+                [constructor_priority], [
+                    int foo( void ) __attribute__((__constructor__(65535/2)));
+                ],
                 [constructor], [
                     int foo( void ) __attribute__(($1));
                 ],
@@ -180,6 +184,8 @@ AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
                 [visibility], [
                     int foo_def( void ) __attribute__(($1("default")));
                     int foo_hid( void ) __attribute__(($1("hidden")));
+                    int foo_int( void ) __attribute__(($1("internal")));
+                    int foo_pro( void ) __attribute__(($1("protected")));
                 ],
                 [warning], [
                     int foo( void ) __attribute__(($1("")));
diff --git a/build-aux/m4/ax_openmp.m4 b/build-aux/m4/ax_openmp.m4
new file mode 100644
index 000000000..866e1d664
--- /dev/null
+++ b/build-aux/m4/ax_openmp.m4
@@ -0,0 +1,123 @@
+# ===========================================================================
+#        https://www.gnu.org/software/autoconf-archive/ax_openmp.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_OPENMP([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
+#
+# DESCRIPTION
+#
+#   This macro tries to find out how to compile programs that use OpenMP a
+#   standard API and set of compiler directives for parallel programming
+#   (see http://www-unix.mcs/)
+#
+#   On success, it sets the OPENMP_CFLAGS/OPENMP_CXXFLAGS/OPENMP_F77FLAGS
+#   output variable to the flag (e.g. -omp) used both to compile *and* link
+#   OpenMP programs in the current language.
+#
+#   NOTE: You are assumed to not only compile your program with these flags,
+#   but also link it with them as well.
+#
+#   If you want to compile everything with OpenMP, you should set:
+#
+#     CFLAGS="$CFLAGS $OPENMP_CFLAGS"
+#     #OR#  CXXFLAGS="$CXXFLAGS $OPENMP_CXXFLAGS"
+#     #OR#  FFLAGS="$FFLAGS $OPENMP_FFLAGS"
+#
+#   (depending on the selected language).
+#
+#   The user can override the default choice by setting the corresponding
+#   environment variable (e.g. OPENMP_CFLAGS).
+#
+#   ACTION-IF-FOUND is a list of shell commands to run if an OpenMP flag is
+#   found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it is
+#   not found. If ACTION-IF-FOUND is not specified, the default action will
+#   define HAVE_OPENMP.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2015 John W. Peterson <jwpeterson@gmail.com>
+#   Copyright (c) 2016 Nick R. Papior <nickpapior@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 13
+
+AC_DEFUN([AX_OPENMP], [
+AC_PREREQ([2.69]) dnl for _AC_LANG_PREFIX
+
+AC_CACHE_CHECK([for OpenMP flag of _AC_LANG compiler], ax_cv_[]_AC_LANG_ABBREV[]_openmp, [save[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
+ax_cv_[]_AC_LANG_ABBREV[]_openmp=unknown
+# Flags to try:  -fopenmp (gcc), -mp (SGI & PGI),
+#                -qopenmp (icc>=15), -openmp (icc),
+#                -xopenmp (Sun), -omp (Tru64),
+#                -qsmp=omp (AIX),
+#                none
+ax_openmp_flags="-fopenmp -openmp -qopenmp -mp -xopenmp -omp -qsmp=omp none"
+if test "x$OPENMP_[]_AC_LANG_PREFIX[]FLAGS" != x; then
+  ax_openmp_flags="$OPENMP_[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flags"
+fi
+for ax_openmp_flag in $ax_openmp_flags; do
+  case $ax_openmp_flag in
+    none) []_AC_LANG_PREFIX[]FLAGS=$save[]_AC_LANG_PREFIX[] ;;
+    *) []_AC_LANG_PREFIX[]FLAGS="$save[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flag" ;;
+  esac
+  AC_LINK_IFELSE([AC_LANG_SOURCE([[
+@%:@include <omp.h>
+
+static void
+parallel_fill(int * data, int n)
+{
+  int i;
+@%:@pragma omp parallel for
+  for (i = 0; i < n; ++i)
+    data[i] = i;
+}
+
+int
+main()
+{
+  int arr[100000];
+  omp_set_num_threads(2);
+  parallel_fill(arr, 100000);
+  return 0;
+}
+]])],[ax_cv_[]_AC_LANG_ABBREV[]_openmp=$ax_openmp_flag; break],[])
+done
+[]_AC_LANG_PREFIX[]FLAGS=$save[]_AC_LANG_PREFIX[]FLAGS
+])
+if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" = "xunknown"; then
+  m4_default([$2],:)
+else
+  if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" != "xnone"; then
+    OPENMP_[]_AC_LANG_PREFIX[]FLAGS=$ax_cv_[]_AC_LANG_ABBREV[]_openmp
+  fi
+  m4_default([$1], [AC_DEFINE(HAVE_OPENMP,1,[Define if OpenMP is enabled])])
+fi
+])dnl AX_OPENMP
diff --git a/build-aux/m4/ax_pthread.m4 b/build-aux/m4/ax_pthread.m4
index d383ad5c6..d218d1af7 100644
--- a/build-aux/m4/ax_pthread.m4
+++ b/build-aux/m4/ax_pthread.m4
@@ -19,10 +19,10 @@
 #   is necessary on AIX to use the special cc_r compiler alias.)
 #
 #   NOTE: You are assumed to not only compile your program with these flags,
-#   but also link it with them as well. e.g. you should link with
+#   but also to link with them as well. For example, you might link with
 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
 #
-#   If you are only building threads programs, you may wish to use these
+#   If you are only building threaded programs, you may wish to use these
 #   variables in your default LIBS, CFLAGS, and CC:
 #
 #     LIBS="$PTHREAD_LIBS $LIBS"
@@ -30,8 +30,8 @@
 #     CC="$PTHREAD_CC"
 #
 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
-#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
-#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
+#   has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to
+#   that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
 #
 #   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
 #   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
@@ -82,35 +82,40 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 21
+#serial 22
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
 AC_REQUIRE([AC_CANONICAL_HOST])
+AC_REQUIRE([AC_PROG_CC])
+AC_REQUIRE([AC_PROG_SED])
 AC_LANG_PUSH([C])
 ax_pthread_ok=no
 
 # We used to check for pthread.h first, but this fails if pthread.h
-# requires special compiler flags (e.g. on True64 or Sequent).
+# requires special compiler flags (e.g. on Tru64 or Sequent).
 # It gets checked for in the link test anyway.
 
 # First of all, check if the user has set any of the PTHREAD_LIBS,
 # etcetera environment variables, and if threads linking works using
 # them:
-if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
-        AC_TRY_LINK_FUNC([pthread_join], [ax_pthread_ok=yes])
-        AC_MSG_RESULT([$ax_pthread_ok])
-        if test x"$ax_pthread_ok" = xno; then
-                PTHREAD_LIBS=""
-                PTHREAD_CFLAGS=""
-        fi
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
+if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
+	ax_pthread_save_CC="$CC"
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+	AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
+	AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
+	AC_MSG_RESULT([$ax_pthread_ok])
+	if test "x$ax_pthread_ok" = "xno"; then
+		PTHREAD_LIBS=""
+		PTHREAD_CFLAGS=""
+	fi
+	CC="$ax_pthread_save_CC"
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
 fi
 
 # We must check for the threads library under a number of different
@@ -123,7 +128,7 @@ fi
 # which indicates that we try without any flags at all, and "pthread-config"
 # which is a program returning the flags for the Pth emulation library.
 
-ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
 
 # The ordering *is* (sometimes) important.  Some notes on the
 # individual items follow:
@@ -132,186 +137,334 @@ ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mt
 # none: in case threads are in libc; should be tried before -Kthread and
 #       other compiler flags to prevent continual compiler warnings
 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
-# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
-# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
-# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
-# -pthreads: Solaris/gcc
-# -mthreads: Mingw32/gcc, Lynx/gcc
+# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64
+#           (Note: HP C rejects this with "bad form for `-t' option")
+# -pthreads: Solaris/gcc (Note: HP C also rejects)
 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
-#      doesn't hurt to check since this sometimes defines pthreads too;
-#      also defines -D_REENTRANT)
-#      ... -mt is also the pthreads flag for HP/aCC
+#      doesn't hurt to check since this sometimes defines pthreads and
+#      -D_REENTRANT too), HP C (must be checked before -lpthread, which
+#      is present but should not be used directly; and before -mthreads,
+#      because the compiler interprets this as "-mt" + "-hreads")
+# -mthreads: Mingw32/gcc, Lynx/gcc
 # pthread: Linux, etcetera
 # --thread-safe: KAI C++
 # pthread-config: use pthread-config program (for GNU Pth library)
 
-case ${host_os} in
-        solaris*)
+case $host_os in
 
-        # On Solaris (at least, for some versions), libc contains stubbed
-        # (non-functional) versions of the pthreads routines, so link-based
-        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
-        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
-        # a function called by this macro, so we could check for that, but
-        # who knows whether they'll stub that too in a future libc.)  So,
-        # we'll just look for -pthreads and -lpthread first:
+	freebsd*)
 
-        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
-        ;;
+	# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+	# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
 
-        darwin*)
-        ax_pthread_flags="-pthread $ax_pthread_flags"
-        ;;
+	ax_pthread_flags="-kthread lthread $ax_pthread_flags"
+	;;
+
+	hpux*)
+
+	# From the cc(1) man page: "[-mt] Sets various -D flags to enable
+	# multi-threading and also sets -lpthread."
+
+	ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags"
+	;;
+
+	openedition*)
+
+	# IBM z/OS requires a feature-test macro to be defined in order to
+	# enable POSIX threads at all, so give the user a hint if this is
+	# not set. (We don't define these ourselves, as they can affect
+	# other portions of the system API in unpredictable ways.)
+
+	AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
+	    [
+#	     if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
+	     AX_PTHREAD_ZOS_MISSING
+#	     endif
+	    ],
+	    [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
+	;;
+
+	solaris*)
+
+	# On Solaris (at least, for some versions), libc contains stubbed
+	# (non-functional) versions of the pthreads routines, so link-based
+	# tests will erroneously succeed. (N.B.: The stubs are missing
+	# pthread_cleanup_push, or rather a function called by this macro,
+	# so we could check for that, but who knows whether they'll stub
+	# that too in a future libc.)  So we'll check first for the
+	# standard Solaris way of linking pthreads (-mt -lpthread).
+
+	ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+	;;
 esac
 
-# Clang doesn't consider unrecognized options an error unless we specify
-# -Werror. We throw in some extra Clang-specific options to ensure that
-# this doesn't happen for GCC, which also accepts -Werror.
+# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
 
-AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
-save_CFLAGS="$CFLAGS"
-ax_pthread_extra_flags="-Werror"
-CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
-                  [AC_MSG_RESULT([yes])],
-                  [ax_pthread_extra_flags=
-                   AC_MSG_RESULT([no])])
-CFLAGS="$save_CFLAGS"
+AS_IF([test "x$GCC" = "xyes"],
+      [ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"])
 
-if test x"$ax_pthread_ok" = xno; then
-for flag in $ax_pthread_flags; do
+# The presence of a feature test macro requesting re-entrant function
+# definitions is, on some systems, a strong hint that pthreads support is
+# correctly enabled
 
-        case $flag in
-                none)
-                AC_MSG_CHECKING([whether pthreads work without any flags])
-                ;;
+case $host_os in
+	darwin* | hpux* | linux* | osf* | solaris*)
+	ax_pthread_check_macro="_REENTRANT"
+	;;
 
-                -*)
-                AC_MSG_CHECKING([whether pthreads work with $flag])
-                PTHREAD_CFLAGS="$flag"
-                ;;
+	aix* | freebsd*)
+	ax_pthread_check_macro="_THREAD_SAFE"
+	;;
 
-                pthread-config)
-                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
-                if test x"$ax_pthread_config" = xno; then continue; fi
-                PTHREAD_CFLAGS="`pthread-config --cflags`"
-                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
-                ;;
+	*)
+	ax_pthread_check_macro="--"
+	;;
+esac
+AS_IF([test "x$ax_pthread_check_macro" = "x--"],
+      [ax_pthread_check_cond=0],
+      [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"])
 
-                *)
-                AC_MSG_CHECKING([for the pthreads library -l$flag])
-                PTHREAD_LIBS="-l$flag"
-                ;;
-        esac
+# Are we compiling with Clang?
 
-        save_LIBS="$LIBS"
-        save_CFLAGS="$CFLAGS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ax_pthread_extra_flags"
+AC_CACHE_CHECK([whether $CC is Clang],
+    [ax_cv_PTHREAD_CLANG],
+    [ax_cv_PTHREAD_CLANG=no
+     # Note that Autoconf sets GCC=yes for Clang as well as GCC
+     if test "x$GCC" = "xyes"; then
+	AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
+	    [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
+#	     if defined(__clang__) && defined(__llvm__)
+	     AX_PTHREAD_CC_IS_CLANG
+#	     endif
+	    ],
+	    [ax_cv_PTHREAD_CLANG=yes])
+     fi
+    ])
+ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
 
-        # Check for various functions.  We must include pthread.h,
-        # since some functions may be macros.  (On the Sequent, we
-        # need a special flag -Kthread to make this header compile.)
-        # We check for pthread_join because it is in -lpthread on IRIX
-        # while pthread_create is in libc.  We check for pthread_attr_init
-        # due to DEC craziness with -lpthreads.  We check for
-        # pthread_cleanup_push because it is one of the few pthread
-        # functions on Solaris that doesn't have a non-functional libc stub.
-        # We try pthread_create on general principles.
-        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_create(&th, 0, start_routine, 0);
-                        pthread_join(th, 0);
-                        pthread_attr_init(&attr);
-                        pthread_cleanup_push(routine, 0);
-                        pthread_cleanup_pop(0) /* ; */])],
-                [ax_pthread_ok=yes],
-                [])
+ax_pthread_clang_warning=no
 
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
+# Clang needs special handling, because older versions handle the -pthread
+# option in a rather... idiosyncratic way
 
-        AC_MSG_RESULT([$ax_pthread_ok])
-        if test "x$ax_pthread_ok" = xyes; then
-                break;
-        fi
+if test "x$ax_pthread_clang" = "xyes"; then
 
-        PTHREAD_LIBS=""
-        PTHREAD_CFLAGS=""
+	# Clang takes -pthread; it has never supported any other flag
+
+	# (Note 1: This will need to be revisited if a system that Clang
+	# supports has POSIX threads in a separate library.  This tends not
+	# to be the way of modern systems, but it's conceivable.)
+
+	# (Note 2: On some systems, notably Darwin, -pthread is not needed
+	# to get POSIX threads support; the API is always present and
+	# active.  We could reasonably leave PTHREAD_CFLAGS empty.  But
+	# -pthread does define _REENTRANT, and while the Darwin headers
+	# ignore this macro, third-party headers might not.)
+
+	PTHREAD_CFLAGS="-pthread"
+	PTHREAD_LIBS=
+
+	ax_pthread_ok=yes
+
+	# However, older versions of Clang make a point of warning the user
+	# that, in an invocation where only linking and no compilation is
+	# taking place, the -pthread option has no effect ("argument unused
+	# during compilation").  They expect -pthread to be passed in only
+	# when source code is being compiled.
+	#
+	# Problem is, this is at odds with the way Automake and most other
+	# C build frameworks function, which is that the same flags used in
+	# compilation (CFLAGS) are also used in linking.  Many systems
+	# supported by AX_PTHREAD require exactly this for POSIX threads
+	# support, and in fact it is often not straightforward to specify a
+	# flag that is used only in the compilation phase and not in
+	# linking.  Such a scenario is extremely rare in practice.
+	#
+	# Even though use of the -pthread flag in linking would only print
+	# a warning, this can be a nuisance for well-run software projects
+	# that build with -Werror.  So if the active version of Clang has
+	# this misfeature, we search for an option to squash it.
+
+	AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
+	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
+	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
+	     # Create an alternate version of $ac_link that compiles and
+	     # links in two steps (.c -> .o, .o -> exe) instead of one
+	     # (.c -> exe), because the warning occurs only in the second
+	     # step
+	     ax_pthread_save_ac_link="$ac_link"
+	     ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
+	     ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+	     ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
+	     ax_pthread_save_CFLAGS="$CFLAGS"
+	     for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
+		AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
+		CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
+		ac_link="$ax_pthread_save_ac_link"
+		AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+		    [ac_link="$ax_pthread_2step_ac_link"
+		     AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+			 [break])
+		    ])
+	     done
+	     ac_link="$ax_pthread_save_ac_link"
+	     CFLAGS="$ax_pthread_save_CFLAGS"
+	     AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
+	     ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
+	    ])
+
+	case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
+		no | unknown) ;;
+		*) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
+	esac
+
+fi # $ax_pthread_clang = yes
+
+if test "x$ax_pthread_ok" = "xno"; then
+for ax_pthread_try_flag in $ax_pthread_flags; do
+
+	case $ax_pthread_try_flag in
+		none)
+		AC_MSG_CHECKING([whether pthreads work without any flags])
+		;;
+
+		-mt,pthread)
+		AC_MSG_CHECKING([whether pthreads work with -mt -lpthread])
+		PTHREAD_CFLAGS="-mt"
+		PTHREAD_LIBS="-lpthread"
+		;;
+
+		-*)
+		AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
+		PTHREAD_CFLAGS="$ax_pthread_try_flag"
+		;;
+
+		pthread-config)
+		AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+		AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
+		PTHREAD_CFLAGS="`pthread-config --cflags`"
+		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+		;;
+
+		*)
+		AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
+		PTHREAD_LIBS="-l$ax_pthread_try_flag"
+		;;
+	esac
+
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+
+	# Check for various functions.  We must include pthread.h,
+	# since some functions may be macros.  (On the Sequent, we
+	# need a special flag -Kthread to make this header compile.)
+	# We check for pthread_join because it is in -lpthread on IRIX
+	# while pthread_create is in libc.  We check for pthread_attr_init
+	# due to DEC craziness with -lpthreads.  We check for
+	# pthread_cleanup_push because it is one of the few pthread
+	# functions on Solaris that doesn't have a non-functional libc stub.
+	# We try pthread_create on general principles.
+
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+#			if $ax_pthread_check_cond
+#			 error "$ax_pthread_check_macro must be defined"
+#			endif
+			static void routine(void *a) { a = 0; }
+			static void *start_routine(void *a) { return a; }],
+		       [pthread_t th; pthread_attr_t attr;
+			pthread_create(&th, 0, start_routine, 0);
+			pthread_join(th, 0);
+			pthread_attr_init(&attr);
+			pthread_cleanup_push(routine, 0);
+			pthread_cleanup_pop(0) /* ; */])],
+	    [ax_pthread_ok=yes],
+	    [])
+
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
+
+	AC_MSG_RESULT([$ax_pthread_ok])
+	AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
+
+	PTHREAD_LIBS=""
+	PTHREAD_CFLAGS=""
 done
 fi
 
 # Various other checks:
-if test "x$ax_pthread_ok" = xyes; then
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+if test "x$ax_pthread_ok" = "xyes"; then
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
 
-        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
-        AC_MSG_CHECKING([for joinable pthread attribute])
-        attr_name=unknown
-        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
-            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
-                           [int attr = $attr; return attr /* ; */])],
-                [attr_name=$attr; break],
-                [])
-        done
-        AC_MSG_RESULT([$attr_name])
-        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
-            AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
-                               [Define to necessary symbol if this constant
-                                uses a non-standard name on your system.])
-        fi
+	# Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+	AC_CACHE_CHECK([for joinable pthread attribute],
+	    [ax_cv_PTHREAD_JOINABLE_ATTR],
+	    [ax_cv_PTHREAD_JOINABLE_ATTR=unknown
+	     for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+		 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
+						 [int attr = $ax_pthread_attr; return attr /* ; */])],
+				[ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
+				[])
+	     done
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
+	       test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
+	       test "x$ax_pthread_joinable_attr_defined" != "xyes"],
+	      [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
+				  [$ax_cv_PTHREAD_JOINABLE_ATTR],
+				  [Define to necessary symbol if this constant
+				   uses a non-standard name on your system.])
+	       ax_pthread_joinable_attr_defined=yes
+	      ])
 
-        AC_MSG_CHECKING([if more special flags are required for pthreads])
-        flag=no
-        case ${host_os} in
-            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
-            osf* | hpux*) flag="-D_REENTRANT";;
-            solaris*)
-            if test "$GCC" = "yes"; then
-                flag="-D_REENTRANT"
-            else
-                # TODO: What about Clang on Solaris?
-                flag="-mt -D_REENTRANT"
-            fi
-            ;;
-        esac
-        AC_MSG_RESULT([$flag])
-        if test "x$flag" != xno; then
-            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
-        fi
+	AC_CACHE_CHECK([whether more special flags are required for pthreads],
+	    [ax_cv_PTHREAD_SPECIAL_FLAGS],
+	    [ax_cv_PTHREAD_SPECIAL_FLAGS=no
+	     case $host_os in
+	     solaris*)
+	     ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
+	     ;;
+	     esac
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
+	       test "x$ax_pthread_special_flags_added" != "xyes"],
+	      [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
+	       ax_pthread_special_flags_added=yes])
 
-        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
-            [ax_cv_PTHREAD_PRIO_INHERIT], [
-                AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
-                                                [[int i = PTHREAD_PRIO_INHERIT;]])],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
-            ])
-        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
-            [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
+	AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
+	    [ax_cv_PTHREAD_PRIO_INHERIT],
+	    [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
+					     [[int i = PTHREAD_PRIO_INHERIT;]])],
+			    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
+			    [ax_cv_PTHREAD_PRIO_INHERIT=no])
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \
+	       test "x$ax_pthread_prio_inherit_defined" != "xyes"],
+	      [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])
+	       ax_pthread_prio_inherit_defined=yes
+	      ])
 
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
 
-        # More AIX lossage: compile with *_r variant
-        if test "x$GCC" != xyes; then
-            case $host_os in
-                aix*)
-                AS_CASE(["x/$CC"],
-                  [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
-                  [#handle absolute path differently from PATH based program lookup
-                   AS_CASE(["x$CC"],
-                     [x/*],
-                     [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
-                     [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
-                ;;
-            esac
-        fi
+	# More AIX lossage: compile with *_r variant
+	if test "x$GCC" != "xyes"; then
+	    case $host_os in
+		aix*)
+		AS_CASE(["x/$CC"],
+		    [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
+		    [#handle absolute path differently from PATH based program lookup
+		     AS_CASE(["x$CC"],
+			 [x/*],
+			 [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
+			 [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+		;;
+	    esac
+	fi
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
@@ -321,12 +474,12 @@ AC_SUBST([PTHREAD_CFLAGS])
 AC_SUBST([PTHREAD_CC])
 
 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
-if test x"$ax_pthread_ok" = xyes; then
-        ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
-        :
+if test "x$ax_pthread_ok" = "xyes"; then
+	ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
+	:
 else
-        ax_pthread_ok=no
-        $2
+	ax_pthread_ok=no
+	$2
 fi
 AC_LANG_POP
 ])dnl AX_PTHREAD
diff --git a/configure.ac b/configure.ac
index b61acf468..75a7aeba8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -40,9 +40,6 @@ else
   CXXFLAGS_overridden=no
 fi
 
-# Zcash requries C++11 compatibility; set it early:
-CXXFLAGS="-std=c++11 $CXXFLAGS"
-
 AC_PROG_CXX
 m4_ifdef([AC_PROG_OBJCXX],[AC_PROG_OBJCXX])
 
@@ -54,6 +51,8 @@ case $host in
      lt_cv_deplibs_check_method="pass_all"
   ;;
 esac
+dnl Require C++11 compiler (no GNU extensions)
+AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
 dnl Libtool init checks.
 LT_INIT([pic-only])
 
@@ -690,6 +689,15 @@ if test x$enable_rust != xno; then
   RUST_LIBS="-lrustzcash"
 fi
 
+dnl Check for OpenMP support
+AX_OPENMP(
+  [AC_DEFINE(HAVE_OPENMP, 1, [Define if OpenMP is enabled])
+   AM_CONDITIONAL([HAVE_OPENMP], [true])
+   CXXFLAGS="$CXXFLAGS $OPENMP_CXXFLAGS"],
+  [AC_MSG_WARN([OpenMP not supported, disabling multithreading])
+   AC_DEFINE(HAVE_OPENMP, 0, [Define if OpenMP is enabled])
+   AM_CONDITIONAL([HAVE_OPENMP], [false])])
+
 # Gitian uses a config.site that sets depends_prefix, and then sets --prefix=/
 # build.sh just uses --prefix
 if test x$depends_prefix != x; then
@@ -698,7 +706,7 @@ else
   LIBSNARK_DEPINST="$prefix"
 fi
 
-LIBZCASH_LIBS="-lgmp -lgmpxx -lboost_system-mt -lcrypto -lsodium -fopenmp $RUST_LIBS"
+LIBZCASH_LIBS="-lgmp -lgmpxx -lboost_system-mt -lcrypto -lsodium $RUST_LIBS"
 
 CXXFLAGS_TEMP="$CXXFLAGS"
 LIBS_TEMP="$LIBS"
diff --git a/depends/builders/darwin.mk b/depends/builders/darwin.mk
index b366460e6..27f550ab0 100644
--- a/depends/builders/darwin.mk
+++ b/depends/builders/darwin.mk
@@ -7,11 +7,11 @@ build_darwin_OTOOL: = $(shell xcrun -f otool)
 build_darwin_NM: = $(shell xcrun -f nm)
 build_darwin_INSTALL_NAME_TOOL:=$(shell xcrun -f install_name_tool)
 build_darwin_SHA256SUM = shasum -a 256
-build_darwin_DOWNLOAD = curl --connect-timeout $(DOWNLOAD_CONNECT_TIMEOUT) --retry $(DOWNLOAD_RETRIES) -L -o
+build_darwin_DOWNLOAD = curl --location --fail --connect-timeout $(DOWNLOAD_CONNECT_TIMEOUT) --retry $(DOWNLOAD_RETRIES) -o
 
 #darwin host on darwin builder. overrides darwin host preferences.
 darwin_CC=$(shell xcrun -f clang) -mmacosx-version-min=$(OSX_MIN_VERSION)
-darwin_CXX:=$(shell xcrun -f clang++) -mmacosx-version-min=$(OSX_MIN_VERSION)
+darwin_CXX:=$(shell xcrun -f clang++) -mmacosx-version-min=$(OSX_MIN_VERSION) -stdlib=libc++
 darwin_AR:=$(shell xcrun -f ar)
 darwin_RANLIB:=$(shell xcrun -f ranlib)
 darwin_STRIP:=$(shell xcrun -f strip)
diff --git a/depends/builders/linux.mk b/depends/builders/linux.mk
index 98d0e9de3..b03f42401 100644
--- a/depends/builders/linux.mk
+++ b/depends/builders/linux.mk
@@ -1,2 +1,2 @@
 build_linux_SHA256SUM = sha256sum
-build_linux_DOWNLOAD = wget --timeout=$(DOWNLOAD_CONNECT_TIMEOUT) --tries=$(DOWNLOAD_RETRIES) -nv -O
+build_linux_DOWNLOAD = curl --location --fail --connect-timeout $(DOWNLOAD_CONNECT_TIMEOUT) --retry $(DOWNLOAD_RETRIES) -o
diff --git a/depends/hosts/darwin.mk b/depends/hosts/darwin.mk
index 2958dc50c..4e58bec74 100644
--- a/depends/hosts/darwin.mk
+++ b/depends/hosts/darwin.mk
@@ -1,9 +1,9 @@
-OSX_MIN_VERSION=10.7
-OSX_SDK_VERSION=10.9
+OSX_MIN_VERSION=10.8
+OSX_SDK_VERSION=10.11
 OSX_SDK=$(SDK_PATH)/MacOSX$(OSX_SDK_VERSION).sdk
-LD64_VERSION=241.9
+LD64_VERSION=253.9
 darwin_CC=clang -target $(host) -mmacosx-version-min=$(OSX_MIN_VERSION) --sysroot $(OSX_SDK) -mlinker-version=$(LD64_VERSION)
-darwin_CXX=clang++ -target $(host) -mmacosx-version-min=$(OSX_MIN_VERSION) --sysroot $(OSX_SDK) -mlinker-version=$(LD64_VERSION)
+darwin_CXX=clang++ -target $(host) -mmacosx-version-min=$(OSX_MIN_VERSION) --sysroot $(OSX_SDK) -mlinker-version=$(LD64_VERSION) -stdlib=libc++
 
 darwin_CFLAGS=-pipe
 darwin_CXXFLAGS=$(darwin_CFLAGS)
diff --git a/depends/packages/bdb.mk b/depends/packages/bdb.mk
index df5df6bde..1134e94d0 100644
--- a/depends/packages/bdb.mk
+++ b/depends/packages/bdb.mk
@@ -9,6 +9,12 @@ define $(package)_set_vars
 $(package)_config_opts=--disable-shared --enable-cxx --disable-replication
 $(package)_config_opts_mingw32=--enable-mingw
 $(package)_config_opts_linux=--with-pic
+$(package)_cxxflags=-std=c++11
+endef
+
+define $(package)_preprocess_cmds
+  sed -i.old 's/__atomic_compare_exchange\\(/__atomic_compare_exchange_db(/' src/dbinc/atomic.h && \
+  sed -i.old 's/atomic_init/atomic_init_db/' src/dbinc/atomic.h src/mp/mp_region.c src/mp/mp_mvcc.c src/mp/mp_fget.c src/mutex/mut_method.c src/mutex/mut_tas.c
 endef
 
 define $(package)_config_cmds
diff --git a/depends/packages/boost.mk b/depends/packages/boost.mk
index 7303821be..0c545c4d5 100644
--- a/depends/packages/boost.mk
+++ b/depends/packages/boost.mk
@@ -21,7 +21,7 @@ $(package)_archiver_$(host_os)=$($(package)_ar)
 $(package)_toolset_darwin=darwin
 $(package)_archiver_darwin=$($(package)_libtool)
 $(package)_config_libraries=chrono,filesystem,program_options,system,thread,test
-$(package)_cxxflags=-fvisibility=hidden
+$(package)_cxxflags=-std=c++11 -fvisibility=hidden
 $(package)_cxxflags_linux=-fPIC
 endef
 
diff --git a/depends/packages/googletest.mk b/depends/packages/googletest.mk
index 94880efdb..b10ce89eb 100644
--- a/depends/packages/googletest.mk
+++ b/depends/packages/googletest.mk
@@ -11,8 +11,9 @@ define $(package)_build_cmds
 endef
 
 define $(package)_stage_cmds
-  install -D ./googlemock/make/gmock.a $($(package)_staging_dir)$(host_prefix)/lib/libgmock.a && \
-  install -D ./googletest/make/gtest.a $($(package)_staging_dir)$(host_prefix)/lib/libgtest.a && \
+  mkdir -p $($(package)_staging_dir)$(host_prefix)/lib && \
+  install ./googlemock/make/gmock.a $($(package)_staging_dir)$(host_prefix)/lib/libgmock.a && \
+  install ./googletest/make/gtest.a $($(package)_staging_dir)$(host_prefix)/lib/libgtest.a && \
   cp -a ./googlemock/include $($(package)_staging_dir)$(host_prefix)/ && \
   cp -a ./googletest/include $($(package)_staging_dir)$(host_prefix)/
 endef
diff --git a/depends/packages/zeromq.mk b/depends/packages/zeromq.mk
index 4b335c54c..3cca06dae 100644
--- a/depends/packages/zeromq.mk
+++ b/depends/packages/zeromq.mk
@@ -7,6 +7,7 @@ $(package)_sha256_hash=27d1e82a099228ee85a7ddb2260f40830212402c605a4a10b5e5498a7
 define $(package)_set_vars
   $(package)_config_opts=--without-documentation --disable-shared --disable-curve
   $(package)_config_opts_linux=--with-pic
+  $(package)_cxxflags=-std=c++11
 endef
 
 define $(package)_config_cmds
diff --git a/src/Makefile.am b/src/Makefile.am
index 71b89b96d..797fdcfe9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -46,7 +46,10 @@ $(LIBSECP256K1): $(wildcard secp256k1/src/*) $(wildcard secp256k1/include/*)
 collate-libsnark: $(LIBSNARK)
 
 LIBSNARK_CXXFLAGS = -fPIC -DBINARY_OUTPUT -DNO_PT_COMPRESSION=1
-LIBSNARK_CONFIG_FLAGS = CURVE=ALT_BN128 MULTICORE=1 NO_PROCPS=1 NO_DOCS=1 STATIC=1 NO_SUPERCOP=1 FEATUREFLAGS=-DMONTGOMERY_OUTPUT NO_COPY_DEPINST=1 NO_COMPILE_LIBGTEST=1
+LIBSNARK_CONFIG_FLAGS = CURVE=ALT_BN128 NO_PROCPS=1 NO_DOCS=1 STATIC=1 NO_SUPERCOP=1 FEATUREFLAGS=-DMONTGOMERY_OUTPUT NO_COPY_DEPINST=1 NO_COMPILE_LIBGTEST=1
+if HAVE_OPENMP
+LIBSNARK_CONFIG_FLAGS += MULTICORE=1
+endif
 
 $(LIBSNARK): $(wildcard snark/src/*)
 	$(AM_V_at) CXXFLAGS="$(LIBSNARK_CXXFLAGS)" $(MAKE) $(AM_MAKEFLAGS) -C snark/ install PREFIX=$(srcdir)/build DEPINST="$(LIBSNARK_DEPINST)" $(LIBSNARK_CONFIG_FLAGS) OPTFLAGS="-O2 -march=x86-64"
diff --git a/src/crypto/equihash.cpp b/src/crypto/equihash.cpp
index d22244aa9..d98389861 100644
--- a/src/crypto/equihash.cpp
+++ b/src/crypto/equihash.cpp
@@ -16,6 +16,7 @@
 #include "config/bitcoin-config.h"
 #endif
 
+#include "compat/endian.h"
 #include "crypto/equihash.h"
 #include "util.h"
 
diff --git a/src/reverselock.h b/src/reverselock.h
index db5c626c9..fac1ccb79 100644
--- a/src/reverselock.h
+++ b/src/reverselock.h
@@ -15,10 +15,12 @@ public:
 
     explicit reverse_lock(Lock& lock) : lock(lock) {
         lock.unlock();
+        lock.swap(templock);
     }
 
-    ~reverse_lock() noexcept(false) {
-        lock.lock();
+    ~reverse_lock() {
+        templock.lock();
+        templock.swap(lock);
     }
 
 private:
@@ -26,6 +28,7 @@ private:
     reverse_lock& operator=(reverse_lock const&);
 
     Lock& lock;
+    Lock templock;
 };
 
 #endif // BITCOIN_REVERSELOCK_H
diff --git a/src/snark/Makefile b/src/snark/Makefile
index 32b8609f2..1583facf7 100644
--- a/src/snark/Makefile
+++ b/src/snark/Makefile
@@ -198,13 +198,8 @@ $(LIBGTEST_A): $(GTESTDIR)/src/gtest-all.cc $(DEPINST_EXISTS)
 
 # libsnark.a will contains all of our relevant object files, and we also mash in the .a files of relevant dependencies built by ./prepare-depends.sh
 $(LIBSNARK_A): $(LIB_OBJS) $(AR_LIBS)
-	( \
-	  echo "create $(LIBSNARK_A)"; \
-	  echo "addmod $(LIB_OBJS)"; \
-	  if [ -n "$(AR_LIBS)" ]; then for AR_LIB in $(AR_LIBS); do echo addlib $$AR_LIB; done; fi; \
-	  echo "save"; \
-	  echo "end"; \
-	) | $(AR) -M
+	$(AR) q $(LIBSNARK_A) $(LIB_OBJS)
+	if [ -n "$(AR_LIBS)" ]; then mkdir -p tmp-ar; cd tmp-ar; for AR_LIB in $(AR_LIBS); do $(AR) x $$AR_LIB; done; $(AR) qc $(LIBSNARK_A) tmp-ar/*; cd ..; rm -r tmp-ar; fi;
 	$(AR) s $(LIBSNARK_A)
 
 libsnark.so: $(LIBSNARK_A) $(DEPINST_EXISTS)
diff --git a/src/test/reverselock_tests.cpp b/src/test/reverselock_tests.cpp
index e7e627ae0..8bdff9700 100644
--- a/src/test/reverselock_tests.cpp
+++ b/src/test/reverselock_tests.cpp
@@ -42,22 +42,18 @@ BOOST_AUTO_TEST_CASE(reverselock_errors)
     BOOST_CHECK(failed);
     BOOST_CHECK(!lock.owns_lock());
 
-    // Make sure trying to lock a lock after it has been reverse locked fails
-    failed = false;
-    bool locked = false;
+    // Locking the original lock after it has been taken by a reverse lock
+    // makes no sense. Ensure that the original lock no longer owns the lock
+    // after giving it to a reverse one.
 
     lock.lock();
     BOOST_CHECK(lock.owns_lock());
-
-    try {
+    {
         reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
-        lock.lock();
-        locked = true;
-    } catch(...) {
-        failed = true;
+        BOOST_CHECK(!lock.owns_lock());
     }
 
-    BOOST_CHECK(locked && failed);
+    BOOST_CHECK(failed);
     BOOST_CHECK(lock.owns_lock());
 }
 
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index e73d05cc9..2b481d87a 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -60,7 +60,6 @@ static const unsigned int MAX_FREE_TRANSACTION_CREATE_SIZE = 1000;
 //  unless there is some exceptional network disruption.
 static const unsigned int WITNESS_CACHE_SIZE = COINBASE_MATURITY;
 
-class CAccountingEntry;
 class CBlockIndex;
 class CCoinControl;
 class COutput;
@@ -570,6 +569,86 @@ public:
     }
 };
 
+/**
+ * Internal transfers.
+ * Database key is acentry<account><counter>.
+ */
+class CAccountingEntry
+{
+public:
+    std::string strAccount;
+    CAmount nCreditDebit;
+    int64_t nTime;
+    std::string strOtherAccount;
+    std::string strComment;
+    mapValue_t mapValue;
+    int64_t nOrderPos;  //! position in ordered transaction list
+    uint64_t nEntryNo;
+
+    CAccountingEntry()
+    {
+        SetNull();
+    }
+
+    void SetNull()
+    {
+        nCreditDebit = 0;
+        nTime = 0;
+        strAccount.clear();
+        strOtherAccount.clear();
+        strComment.clear();
+        nOrderPos = -1;
+        nEntryNo = 0;
+    }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        if (!(nType & SER_GETHASH))
+            READWRITE(nVersion);
+        //! Note: strAccount is serialized as part of the key, not here.
+        READWRITE(nCreditDebit);
+        READWRITE(nTime);
+        READWRITE(LIMITED_STRING(strOtherAccount, 65536));
+
+        if (!ser_action.ForRead())
+        {
+            WriteOrderPos(nOrderPos, mapValue);
+
+            if (!(mapValue.empty() && _ssExtra.empty()))
+            {
+                CDataStream ss(nType, nVersion);
+                ss.insert(ss.begin(), '\0');
+                ss << mapValue;
+                ss.insert(ss.end(), _ssExtra.begin(), _ssExtra.end());
+                strComment.append(ss.str());
+            }
+        }
+
+        READWRITE(LIMITED_STRING(strComment, 65536));
+
+        size_t nSepPos = strComment.find("\0", 0, 1);
+        if (ser_action.ForRead())
+        {
+            mapValue.clear();
+            if (std::string::npos != nSepPos)
+            {
+                CDataStream ss(std::vector<char>(strComment.begin() + nSepPos + 1, strComment.end()), nType, nVersion);
+                ss >> mapValue;
+                _ssExtra = std::vector<char>(ss.begin(), ss.end());
+            }
+            ReadOrderPos(nOrderPos, mapValue);
+        }
+        if (std::string::npos != nSepPos)
+            strComment.erase(nSepPos);
+
+        mapValue.erase("n");
+    }
+
+private:
+    std::vector<char> _ssExtra;
+};
 
 
 /** 
@@ -1094,87 +1173,4 @@ public:
     }
 };
 
-
-
-/** 
- * Internal transfers.
- * Database key is acentry<account><counter>.
- */
-class CAccountingEntry
-{
-public:
-    std::string strAccount;
-    CAmount nCreditDebit;
-    int64_t nTime;
-    std::string strOtherAccount;
-    std::string strComment;
-    mapValue_t mapValue;
-    int64_t nOrderPos;  //! position in ordered transaction list
-    uint64_t nEntryNo;
-
-    CAccountingEntry()
-    {
-        SetNull();
-    }
-
-    void SetNull()
-    {
-        nCreditDebit = 0;
-        nTime = 0;
-        strAccount.clear();
-        strOtherAccount.clear();
-        strComment.clear();
-        nOrderPos = -1;
-        nEntryNo = 0;
-    }
-
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
-        if (!(nType & SER_GETHASH))
-            READWRITE(nVersion);
-        //! Note: strAccount is serialized as part of the key, not here.
-        READWRITE(nCreditDebit);
-        READWRITE(nTime);
-        READWRITE(LIMITED_STRING(strOtherAccount, 65536));
-
-        if (!ser_action.ForRead())
-        {
-            WriteOrderPos(nOrderPos, mapValue);
-
-            if (!(mapValue.empty() && _ssExtra.empty()))
-            {
-                CDataStream ss(nType, nVersion);
-                ss.insert(ss.begin(), '\0');
-                ss << mapValue;
-                ss.insert(ss.end(), _ssExtra.begin(), _ssExtra.end());
-                strComment.append(ss.str());
-            }
-        }
-
-        READWRITE(LIMITED_STRING(strComment, 65536));
-
-        size_t nSepPos = strComment.find("\0", 0, 1);
-        if (ser_action.ForRead())
-        {
-            mapValue.clear();
-            if (std::string::npos != nSepPos)
-            {
-                CDataStream ss(std::vector<char>(strComment.begin() + nSepPos + 1, strComment.end()), nType, nVersion);
-                ss >> mapValue;
-                _ssExtra = std::vector<char>(ss.begin(), ss.end());
-            }
-            ReadOrderPos(nOrderPos, mapValue);
-        }
-        if (std::string::npos != nSepPos)
-            strComment.erase(nSepPos);
-
-        mapValue.erase("n");
-    }
-
-private:
-    std::vector<char> _ssExtra;
-};
-
 #endif // BITCOIN_WALLET_WALLET_H