[WIP] Compiler Attributes: support noderef and address_space

This breaks all kinds of things for Clang builds.

Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: "ndesaulniers@google.com" <ndesaulniers@google.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Xiaozhou Liu <liuxiaozhou@bytedance.com>
Signed-off-by: Kees Cook <keescook@chromium.org>