- Export the function added in r265456 rather than the non-existent
  _rtld_debug_postinit(). [1]
- Use __compiler_membar() instead of inline asm in _r_debug_state() and
  _r_debug_postinit(). [2]

Pointy hat to:	markj [1]
Reported by:	attilio [2]
Discussed with:	kib
X-MFC-With:	r265456