So, what is Apple shipping _other_ than GCC? Unless validation means
something other than "meets all the requirements for a hosted or
freestanding implementation".
The "c99" command on MacOS 10.5 (the one that's claimed to conform to
UNIX 03) is documented to be just a wrapper around GCC. I don't have
access to a system I can actually play around with[1], so I can't
confirm it, but it seems to me more likely that they gave it a generous
C99 conformance test than that they fixed the compiler and missed
updating the documentation.
If Apple thought it was important to people, I would expect them to
provide a compiler that at least tried to fully conform to C99, but I
somehow doubt that they think it's worth the effort.
dave
(it's a shame, really, that would almost be worth upgrading from 10.4 for)
[1] It's a lot easier to say "Hey, can I borrow your Macbook to read a
man page for the new OS version?" than "Hey, can I take your
Macbook home tonight to run a C99 conformance test suite?".