https://github.com/libffi/libffi/issues/879
https://gitweb.gentoo.org/repo/gentoo.git/tree/dev-libs/libffi/files/libffi-3.4.7-Revert-Fix-x86-ffi64-calls-with-6-gp-and-some-sse-re.patch

Index: testsuite/libffi.call/struct_int_float.c
--- testsuite/libffi.call/struct_int_float.c.orig
+++ testsuite/libffi.call/struct_int_float.c
@@ -5,6 +5,7 @@
    Originator:	kellda  */
 
 /* { dg-do run } */
+/* { dg-skip-if "libffi bug #879" { *-*-* } { "*" } } */
 #include "ffitest.h"
 
 typedef struct
