pthread_main_np(3) on macOS

The text 02529bf515f8, as OS X 10.11.6, OS X 10.11.5, OS X 10.11.4, OS X 10.11.3, OS X 10.11.2, OS X 10.11.1, OS X 10.11 shipped it.

identify the initial thread

pthread_main_np(3) on macOS now