GMP 6.0.0a on AMD A8-6600K

[Marc Glisse]

This seems to fix it. I thought that removing the line would work as well, 
but it doesn't. Torbjörn, you know best how that whole machinery is 
supposed to work, any opinion?

diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1831,17 +1831,17 @@ case $host in
        *noavx)
         gcc_cflags_noavx="-mno-avx";;
      esac

      case $host in
        X86_64_PATTERN)
         cclist_64="gcc cc"
         gcc_64_cflags="$gcc_cflags -m64"
-       gcc_64_cflags_optlist="cpu arch"
+       gcc_64_cflags_optlist="cpu arch noavx"
         CALLING_CONVENTIONS_OBJS_64='amd64call.lo amd64check$U.lo'
         SPEED_CYCLECOUNTER_OBJ_64=x86_64.lo
         cyclecounter_size_64=2

         cclist_x32="gcc cc"
         gcc_x32_cflags="$gcc_cflags -mx32"
         gcc_x32_cflags_optlist="$gcc_64_cflags_optlist"
         CALLING_CONVENTIONS_OBJS_x32="$CALLING_CONVENTIONS_OBJS_64"