Add a few missing llvm/clang patches, update the other ones to be able
to apply with the same patch options onto a fresh upstream llvm/clang
3.4.1 checkout, and use approximately the same header tempate for them.

MFC after:	3 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271931 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f