am 101b5e1f: Merge "Define PTHREAD_KEYS_MAX and _POSIX_THREAD_KEYS_MAX in a POSIX-compliant way."

* commit '101b5e1f6cc4e24635760928b3d2c1e51c1e5774':
  Define PTHREAD_KEYS_MAX and _POSIX_THREAD_KEYS_MAX in a POSIX-compliant way.