am 116bf16d: am 870c6634: am 557c79bf: am b769dcb8: Merge "Update signal.h from bionic with transition from SIGRTMIN to __SIGRTMIN"

* commit '116bf16d1f822c264573662031ed9be4ba49a9da':
  Update signal.h from bionic with transition from SIGRTMIN to __SIGRTMIN