[phobos] [D-Programming-Language/phobos] 015d50: Simplify string escaping in win64.mak

[GitHub via phobos]

  Branch: refs/heads/test-versions
  Home:   https://github.com/D-Programming-Language/phobos
  Commit: 015d50cc8875d1fd066d40cf4887c3fb78acc35f
      https://github.com/D-Programming-Language/phobos/commit/015d50cc8875d1fd066d40cf4887c3fb78acc35f
  Author: Dicebot <public at dicebot.lv>
  Date:   2014-08-15 (Fri, 15 Aug 2014)

  Changed paths:
    M win64.mak

  Log Message:
  -----------
  Simplify string escaping in win64.mak

Original approach was causing problems with unqualified paths
like CC=cl