[PATCH] Implement __declspec(selectany) under -fms-extensions

[Rafael Ávila de Espíndola]

  Should

  static int x;
  extern __declspec(selectany) int x;

  work or be rejected? If rejected, LGTM with it added as a test.

http://llvm-reviews.chandlerc.com/D814

BRANCH
  selectany

ARCANIST PROJECT
  clang