compiler*.h: sync include/linux/compiler*.h with Linux 3.16

Copy them from Linux v3.16 tag.
My main motivation of this commit is to add compiler-clang.h.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Jeroen Hofstee <jeroen@myspectrum.nl>
6 files changed