ninja&make/mac: Support :identifier, :rfc1034identifier suffices.

BUG=280718
R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/24175003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1733 78cadc50-ecff-11dd-a971-7dbc132099af