You're using gcc without properly installing the gcc fixed
include files. Or you ran fixincludes after installing gcc
w/o moving the gcc supplied varargs.h and stdarg.h files
out of the way and moving them back again later. This often
happens when people install gcc from a binary distribution.
If there's a tmp directory in gcc's include directory, fixincludes
didn't complete. You should have run "just-fixinc" instead.
Another possible cause is that you're using ``gcc -I/usr/include.''
Reinstall gcc or upgrade to gcc 2.8.0 or later, which doesn't
require a reinstallation after every OS upgrade, if you
run Solaris 2.5 or later.