Also a couple bug fixes:
	* dyn_load.c (GC_FirstDLOpenedLinkMap): Declare _DYNAMIC as
	`weak'.
	* misc.c (GC_init_inner): If QUICK_THREADS defined, compute
	GC_stackbottom.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@26650 138bc75d-0d04-0410-961f-82ee72b054a4