Upgrade devel/llvm and lang/llvm-gcc4 to LLVM 2.2.
Switch llvm-gcc4 from the deprecated gcc 4.0 based version to a new gcc
4.2 based release.
See the release notes for details:
Upgrade to LLVM 2.1, the latest release.
A couple patchs are included from HEAD that didn't make the release, but
fix use-after-free bugs.
Submitted by: Emil Mikulic <emil at cs dot rmit dot edu dot au>