diff -r f24cd8bc5250 Modules/_ctypes/libffi_osx/ffi.c
--- a/Modules/_ctypes/libffi_osx/ffi.c	Thu Jun 04 21:58:16 2015 +1000
+++ b/Modules/_ctypes/libffi_osx/ffi.c	Thu Jun 04 21:43:19 2015 +0700
@@ -102,7 +102,7 @@
 /* Perform machine independent ffi_cif preparation, then call
    machine dependent routine. */
 
-#if defined(X86_DARWIN)
+#if defined(X86_DARWIN) && !defined __x86_64__
 
 static inline bool
 struct_on_stack(
@@ -125,7 +125,7 @@
 	}
 }
 
-#endif	// defined(X86_DARWIN)
+#endif	// defined(X86_DARWIN) && !defined __x86_64__
 
 // Arguments' ffi_type->alignment must be nonzero.
 ffi_status