GC_please_stop     68 gc/win32_threads.c volatile GC_bool GC_please_stop = FALSE;
GC_please_stop    145 gc/win32_threads.c   while (GC_please_stop) Sleep(20);
GC_please_stop    243 gc/win32_threads.c   GC_please_stop = TRUE;
GC_please_stop    289 gc/win32_threads.c   GC_please_stop = FALSE;