[PATCH] Avoid std::function until PR19030 is fixed

[Chandler Carruth]

  This looks good.

  Can you also (in a separate patch) make it clear that we expect ToT Clang to be able to bootstrap on windows? This should go in the "host toolchains" section somewhere. Essentially, we should write down that we do expect to develop these two in lock-step.

  Naturally, a bot is next. =]

http://llvm-reviews.chandlerc.com/D2930

BRANCH
  ban-std-function

ARCANIST PROJECT
  llvm