[PATCH] cpp11-migrate: Add '-supports' command line switch.

[Edwin Vane]

  How about just `-for-compiler`. I'm in favour of a comma-separated list. Just because -I and friends don't do it this way way doesn't mean we can't. This is a completely different option and comma-separated values is quite common.

http://llvm-reviews.chandlerc.com/D1202

BRANCH
  supports-cmd-2

ARCANIST PROJECT
  clang-tools-extra