support ggc hash_map and hash_set

gcc/ChangeLog:

	* alloc-pool.c: Include coretypes.h.
	* cgraph.h, dbxout.c, dwarf2out.c, except.c, except.h, function.c,
	function.h, symtab.c, tree-cfg.c, tree-eh.c: Use hash_map and
	hash_set instead of htab.
	* ggc-page.c (in_gc): New variable.
	(ggc_free): Do nothing if a collection is taking place.
	(ggc_collect): Set in_gc appropriately.
	* ggc.h (gt_ggc_mx(const char *)): New function.
	(gt_pch_nx(const char *)): Likewise.
	(gt_ggc_mx(int)): Likewise.
	(gt_pch_nx(int)): Likewise.
	* hash-map.h (hash_map::hash_entry::ggc_mx): Likewise.
	(hash_map::hash_entry::pch_nx): Likewise.
	(hash_map::hash_entry::pch_nx_helper): Likewise.
(hash_map::hash_map): Adjust.
(hash_map::create_ggc): New function.
(gt_ggc_mx): Likewise.
(gt_pch_nx): Likewise.
	* hash-set.h (default_hashset_traits::ggc_mx): Likewise.
(default_hashset_traits::pch_nx): Likewise.
(hash_set::hash_entry::ggc_mx): Likewise.
(hash_set::hash_entry::pch_nx): Likewise.
(hash_set::hash_entry::pch_nx_helper): Likewise.
(hash_set::hash_set): Adjust.
(hash_set::create_ggc): New function.
(hash_set::elements): Likewise.
(gt_ggc_mx): Likewise.
(gt_pch_nx): Likewise.
	* hash-table.h (hash_table::hash_table): Adjust.
(hash_table::m_ggc): New member.
	(hash_table::~hash_table): Adjust.
	(hash_table::expand): Likewise.
	(hash_table::empty): Likewise.
(gt_ggc_mx): New function.
	(hashtab_entry_note_pointers): Likewise.
(gt_pch_nx): Likewise.

From-SVN: r214834