With new linux ports infrastructure introduction USE_GL=linux
is deprecated (it can't handle multiple linux base ports at a
ports tree). USE_LINUX_APPS should be used instead. Beware
that only fc4 (the default for all FreeBSD versions) and f8
is supported by new linux infrastructure (f10 is upcomming).
Submitted by: bsam (me)
Approved by: miwi (co maintainer)