Convert cpplib to use libiberty/hashtab.c.

	Convert cpplib to use libiberty/hashtab.c.

	* cpplib.h (struct cpp_reader): Make hashtab and
	all_include_files of type 'struct htab *'.  Delete HASHSIZE
	and ALL_INCLUDE_HASHSIZE macros.

	* cpphash.h: Update prototypes.
	(struct hashnode): Remove next, prev, and bucket_hdr members.
	Make length a size_t.  Add hash member.
	(struct ihash): Remove next member.  Add hash member.  Make
	name a flexible array member.

	* cppfiles.c: Include hashtab.h.
	(include_hash): Delete.
	(IHASHSIZE): New macro.
	(hash_IHASH, eq_IHASH, _cpp_init_include_hash): New functions.
	(cpp_included): Do the hash lookup here.
	(_cpp_find_include_file): Rewrite.
	(cpp_read_file): Put the "fake" hash entry into the hash
	table.  Honor the control_macro, if it turns out we've seen
	the file before.  Don't push the buffer here.
	(_cpp_read_include_file): Push the buffer here.
	(OMODES): New macro.  Use it whenever we call open(2).

	* cpphash.c: Include hashtab.h.
	(hash_HASHNODE, eq_HASHNODE, del_HASHNODE, dump_hash_helper,
	_cpp_init_macro_hash, _cpp_dump_macro_hash, _cpp_make_hashnode,
	_cpp_lookup_slot): New functions.
	(HASHSIZE): new macro.
	(hashf, _cpp_install, _cpp_delete_macro): Delete.
	(_cpp_lookup): Use hashtab.h routines.

	* cppinit.c: Include hashtab.h.
	(cpp_reader_init): Call _cpp_init_macro_hash and
	_cpp_init_include_hash.  Don't allocate hashtab directly.
	(cpp_cleanup): Just call htab_delete on pfile->hashtab and
	pfile->all_include_files.
	(initialize_builtins): Use _cpp_make_hashnode and
	htab_find_slot to add hash entries.
	(cpp_finish): Just call _cpp_dump_macro_hash.
	* cpplib.c: Include hashtab.h.
	(do_define): Use _cpp_lookup_slot and _cpp_make_hashnode to
	create hash entries.
	(do_pragma_poison, do_assert): Likewise.
	(do_include): Don't push the buffer here.  Don't increment
	system_include_depth unless _cpp_read_include_file succeeds.
	(do_undef, do_unassert): Use _cpp_lookup_slot and htab_clear_slot
	or htab_remove_elt.
	(do_pragma_implementation): Use alloca to create copy.

	* Makefile.in: Update dependencies.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@32497 138bc75d-0d04-0410-961f-82ee72b054a4