fix 219 gc/dyn_load.c --> fix mutual exclusion with dlopen fix 539 gc/include/private/gc_priv.h --> fix HBLKSIZE fix 203 gc/mach_dep.c add.w #4,sp ; fix stack. fix 571 gc/mach_dep.c --> fix it fix 21 gc/pthread_stop_world.c --> please fix it fix 139 gc/reclaim.c --> potential overflow; fix the code