http://www.opengroup.org/testing/cireport1.4a/
available with a free one-month evaluation or an unlimited license for
$600. The suite is compatible with Make and tests your application's
portability with Motif, X11R5, SVID3, XPG3/XPG4, SPEC1170/UNIX95,
and a host of others.
This is an opportunity to test Linux for conformance with UNIX95 so
perhaps our favorite OS might finally gain UNIX brand conformance,
which I suspect would do a lot towards wider industry acceptance.