As has been pointed out to me, GCC is excessively permissive by default. So...
We need a probe in configure.pl for GCC as the C compiler, and we need to
have -Wall as a default switch on GCC builds. All builds should go without
complaint to be considered passing.
Jarkko's got some truly fascist switches for gcc. Once we're -Wall clean,
those will go in too...
Dan
