Merge llvm trunk r300422 and resolve conflicts.

Update llvm to trunk r290819 and resolve conflicts.

Update llvm to release_39 branch r276489, and resolve conflicts.

Update llvm/clang to r242221.

Merge llvm 3.6.0rc1 from ^/vendor/llvm/dist, merge clang 3.6.0rc1 from
^/vendor/clang/dist, resolve conflicts, and cleanup patches.

Merge llvm 3.5.0 release from ^/vendor/llvm/dist, resolve conflicts, and
preserve our customizations, where necessary.

Import LLVM/clang from vendor stripped of docs/ test/ website/ www/ examples/
in llvm/ and/or llvm/contrib/clang/ respectively.

Approved by: ed (mentor)
Approved by: core