[PATCH] rewrite-includes: Rewrite __has_include(_next) to get rid of a host dependency.

[Benjamin Kramer]

  Closed by commit rL179616 (authored by d0k).

CHANGED PRIOR TO COMMIT
  http://llvm-reviews.chandlerc.com/D594?vs=1440&id=1654#toc

http://llvm-reviews.chandlerc.com/D594

COMMIT
  http://llvm-reviews.chandlerc.com/rL179616