[PATCH] Add a mangler entry point for TBAA rather than using RTTI directly

[Dan Gohman]

  This looks good to me.

  It might be useful to convert the "Itanium" TBAA names to work the same way, instead of re-using the RTTI strings, though that doesn't need to happen here.

http://llvm-reviews.chandlerc.com/D2153

BRANCH
  mangle-tbaa

ARCANIST PROJECT
  clang