thread_start     3702 thread.c           rb_define_singleton_method(rb_cThread, "start", thread_start, -2);
thread_start     3703 thread.c           rb_define_singleton_method(rb_cThread, "fork", thread_start, -2);
thread_start      344 thread_pthread.c   thread_start:
thread_start      361 thread_pthread.c 	    goto thread_start;