secp256k1: Add build-side changes for libsecp256k1

Note: This is added to our existing automake targets rather than as a
libtool-style lib. The switch to libtool-style targets can come later if it
proves to not add any complications.

src/Makefile.am

@@ -1,6 +1,10 @@
 AM_CPPFLAGS =  $(INCLUDES)
 AM_LDFLAGS = $(PTHREAD_CFLAGS)
 
+if USE_LIBSECP256K1
+secp256k1/libsecp256k1.la: $(wildcard secp256k1/src/*) $(wildcard secp256k1/include/*)
+	@$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
+endif
 
 if EMBEDDED_LEVELDB
 LEVELDB_CPPFLAGS += -I$(srcdir)/leveldb/include
@@ -20,6 +24,10 @@ endif
 BITCOIN_CONFIG_INCLUDES=-I$(builddir)/config
 BITCOIN_INCLUDES=-I$(builddir) -I$(builddir)/obj $(BOOST_CPPFLAGS) $(LEVELDB_CPPFLAGS)
 
+if USE_LIBSECP256K1
+BITCOIN_INCLUDES += -I$(srcdir)/secp256k1/include
+endif
+
 LIBBITCOIN_SERVER=libbitcoin_server.a
 LIBBITCOIN_WALLET=libbitcoin_wallet.a
 LIBBITCOIN_COMMON=libbitcoin_common.a
@@ -220,6 +228,11 @@ bitcoind_LDADD = \
   $(LIBBITCOIN_CRYPTO) \
   $(LIBLEVELDB) \
   $(LIBMEMENV)
+
+if USE_LIBSECP256K1
+  bitcoind_LDADD += secp256k1/libsecp256k1.la
+endif
+
 if ENABLE_WALLET
 bitcoind_LDADD += libbitcoin_wallet.a
 endif
@@ -242,6 +255,10 @@ bitcoin_cli_LDADD = \
   $(BOOST_LIBS)
 bitcoin_cli_SOURCES = \
   bitcoin-cli.cpp
+
+if USE_LIBSECP256K1
+  bitcoin_cli_LDADD += secp256k1/libsecp256k1.la
+endif
 bitcoin_cli_CPPFLAGS = $(BITCOIN_INCLUDES)
 #
 
@@ -253,10 +270,11 @@ CLEANFILES = leveldb/libleveldb.a leveldb/libmemenv.a *.gcda *.gcno
 
 DISTCLEANFILES = obj/build.h
 
-EXTRA_DIST = leveldb
+EXTRA_DIST = leveldb secp256k1
 
 clean-local:
 	-$(MAKE) -C leveldb clean
+	-$(MAKE) -C secp256k1 clean
 	rm -f leveldb/*/*.gcno leveldb/helpers/memenv/*.gcno
 	-rm -f config.h