ggc-zone.c (struct alloc_zone): Don't pre-declare, it already comes in with ggc.h.
* ggc-zone.c (struct alloc_zone): Don't pre-declare, it already
comes in with ggc.h. Add a new bool field `dead'.
(destroy_ggc_zone): Don't destroy a zone at once. Instead, only
set the `dead' flag for the dead zone. Wrap a sanity check in
ENABLE_CHECKING.
(ggc_collect_1): Always mark and sweep if a zone has the `dead'
flag set.
(ggc_collect): Free dead zones after collecting.