[parrot/parrot] 8e2cc8: Lock the thread's interp, not ourself

[GitHub]

  Branch: refs/heads/threads
  Home:   https://github.com/parrot/parrot
  Commit: 8e2cc840cbfe35ed735e8c81259c7e3cef6dc081
      https://github.com/parrot/parrot/commit/8e2cc840cbfe35ed735e8c81259c7e3cef6dc081
  Author: Stefan Seifert <nine at detonation.org>
  Date:   2012-03-31 (Sat, 31 Mar 2012)

  Changed paths:
    M src/thread.c

  Log Message:
  -----------
  Lock the thread's interp, not ourself

The lock should protect the block_GC_mark flag of the thread, not
ours.