Well, actually, we seem to use ANSI C; we don't use any GNU extensions other
   than long long that I know of.  Nor should we; other compilers may be
   better or freer, later, and gratuitous dependancies are evil.

actually, quite a bit of our source tree depends on extensions
that gcc provides.  ktrace uses one.  a lot of the 'asm' parts
of the kernel and userland are another.