gmp_4.2.1: prevent calls to mpn_add_nc() if HAVE_NATIVE_mpn_sub_nc is false

When building for aarch64 (ie relying only on generic C code rather
than asm) libgmp.so contains undefined references to __gmpn_add_nc
and __gmpn_sub_nc which causes attempts to link with -lgmp to fail:

 | .../usr/lib/libgmp.so: undefined reference to `__gmpn_sub_nc'
 | .../usr/lib/libgmp.so: undefined reference to `__gmpn_add_nc'

Solution based on a historical patch posted to the gmp mailing list:

  https://gmplib.org/list-archives/gmp-discuss/2006-May/002344.html

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/recipes-support/gmp/gmp_4.2.1.bb b/recipes-support/gmp/gmp_4.2.1.bb
index 5e8ee29..029e728 100644
--- a/recipes-support/gmp/gmp_4.2.1.bb
+++ b/recipes-support/gmp/gmp_4.2.1.bb
@@ -11,6 +11,7 @@ SRC_URI = "https://gmplib.org/download/${BPN}/archive/${BP}.tar.bz2 \
            file://Use-__gnu_inline__-attribute.patch \
            file://gmp_fix_for_automake-1.12.patch \
            file://avoid-h-asm-constraint-for-MIPS.patch \
+           file://prevent-calls-to-mpn_add_nc-if-HAVE_NATIVE_mpn_sub_n.patch \
 "
 
 SRC_URI[md5sum] = "091c56e0e1cca6b09b17b69d47ef18e3"