* c-common.h (RID_FIRST_PQ): New.
	* c-parse.in (objc_pq_context): New.
	(objc parser): Set objc_pq_context rather than calling
	remember_protocol_qualifiers and forget_protocol_qualifiers.
	Don't call save_and_forget_protocol_qualifiers.
	(yylexname): Handle objc protocol qualifiers here.
	* stringpool.c (struct str_header): Replace with sp_hashnode.
	(SP_EMPTY, SP_LEN, SP_TREE, SP_STR, SP_VALID): New.
	(alloc_string): Rename alloc_ident.  Use the SP_ accessors.
	Allocate an IDENTIFIER_NODE for each identifier.
	(FORALL_STRINGS, set_identifier): Delete.
	(FORALL_IDS, expand_string_table, stringpool_statistics): Update.
	(ggc_alloc_string): Use an obstack.
	(get_identifier, maybe_get_identifier, mark_string_hash): Update.
	* tree.h: Update comments.
	(set_identifier): Delete.
	* objc/objc-act.c (N_PQ, saved_pq, saved_not_pq,
	save_and_forget_protocol_qualifiers, forget_protocol_qualifiers,
	remember_protocol_qualifiers): Delete.

From-SVN: r42132