[PATCH] Headers: Provide an ABI compatible max_align_t when _MSC_VER is defined

[Chandler Carruth]

  Looks good (since the actual mangling of this shows that it is in fact exactly the 'double' type).

http://llvm-reviews.chandlerc.com/D2924

BRANCH
  max_align_msvc

ARCANIST PROJECT
  clang