cmd/cgo: fix cgo with gccgo

Change-Id: I1780899255e22c16d7f8e9947609a1c284d7c42e
Reviewed-on: https://go-review.googlesource.com/21690Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/cgo/out.go

@@ -1451,7 +1451,7 @@ const char *_cgoPREFIX_Cfunc_CString(struct __go_string s) {
 
 void *_cgoPREFIX_Cfunc_CBytes(struct __go_open_array b) {
 	char *p = malloc(b.__count);
-	memmove(p, b.__data, b.__count);
+	memmove(p, b.__values, b.__count);
 	return p;
 }