Add a patch for Mesa's glheader.h to teach it about the Intel
compiler(s) (no __cdecl, INLINE means inline). Add a hunk to the
FreeBSD.cf patch to make always prepend -rpath with the -Wl, --
GCC understands it either way, but Intel's icc, for example,
does not -- and need not.
Approved by: enholt (maintainer)
Also reviewed by: netchild (icc guru)