Summary: There's a macro scheme already being used for __has_feature etc. Use it for __has_include too, which makes MSVC happy (it doesn't support __has_include yet, and unguarded use explodes horribly).
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25251
llvm-svn: 283260