Auto merge of #1577 - radix42:v1.0.0-rc1-gitian, r=daira

V1.0.0 rc1 gitian

Removes indeterminism from gitian builds: underlying processor instruction set variant of x86_64 was being detected by the libgmp autoconf process, which caused differences in libgmp and libsnark

depends/Makefile

@@ -8,7 +8,7 @@ NO_WALLET ?=
 NO_UPNP ?=
 FALLBACK_DOWNLOAD_PATH ?= https://z.cash/depends-sources
 
-BUILD = $(shell ./config.guess)
+BUILD ?= $(shell ./config.guess)
 HOST ?= $(BUILD)
 PATCHES_PATH = $(BASEDIR)/patches
 BASEDIR = $(CURDIR)

depends/packages/libgmp.mk

@@ -7,7 +7,7 @@ $(package)_dependencies=
 $(package)_config_opts=--enable-cxx --disable-shared
 
 define $(package)_config_cmds
-  $($(package)_autoconf)
+  $($(package)_autoconf) --host=$(host) --build=$(build)
 endef
 
 define $(package)_build_cmds