removed bogus -trigraph (pointed out by bde), included check of operands (suggested by joerg)
Enforce that only Posix-spec'ed options are being used, so people could use this as a Posixificator of some kind. Document the Posix usage in the man page, so to make it clear what's the difference between Posix c89, and gcc.
code. Basically a shortcut to cc -ansi -trigraphs.