Add separate patch files for all the customizations we have currently
applied to our copy of llvm/clang.  These can be applied in alphabetical
order to a pristine llvm/clang 3.4 release source tree, to result in the
same version used in FreeBSD.

This is intended to clearly document all the changes until now, which
mostly consist of cherry pickings from the respective upstream trunks,
plus a number of hand-written FreeBSD-specific ones.  Hopefully those
can eventually be cleaned up and sent upstream too.

MFC after:	1 week
X-MFC-With:	r263313