We already set this via GCC (patched in) and setting it individually per-package
like this causes redefinition errors if folks try to use the new =3 level.

So, protection is the same without this, and this patch removes
the trouble of upgrading to =3 which we're working on.

https://bugs.gentoo.org/847790
--- a/configure.ac
+++ b/configure.ac
@@ -324,7 +324,7 @@ if test "x${enable_debug}" = xyes; then
 	FORTIFY_CFLAGS=""
 else
 	OPT_CFLAGS="-O3"
-	FORTIFY_CFLAGS="-D_FORTIFY_SOURCE=2"
+	FORTIFY_CFLAGS=""
 fi
 
 # Check for availablility of hardening options