[D-runtime] [D-Programming-Language/druntime] ef74a9: fix getting stack bottom

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/druntime
  Commit: ef74a95768704446fd057ee5c0a7b8ea495d7e1a
      https://github.com/D-Programming-Language/druntime/commit/ef74a95768704446fd057ee5c0a7b8ea495d7e1a
  Author: Walter Bright <walter at walterbright.com>
  Date:   2012-10-07 (Sun, 07 Oct 2012)

  Changed paths:
    M src/core/thread.d

  Log Message:
  -----------
  fix getting stack bottom