move many gc hashtab to hash_table

gcc/

* asan.c, cfgloop.c, cfgloop.h, cgraph.c, cgraph.h,
	config/darwin.c, config/m32c/m32c.c, config/mep/mep.c,
	config/mips/mips.c, config/rs6000/rs6000.c, dwarf2out.c,
	function.c, function.h, gimple-ssa.h, libfuncs.h, optabs.c,
	output.h, rtl.h, sese.c, symtab.c, tree-cfg.c, tree-dfa.c,
	tree-ssa.c, varasm.c: Use hash-table instead of hashtab.
	* doc/gty.texi (for_user): Document new option.
	* gengtype.c (create_user_defined_type): Don't try to get a struct for
	char.
	(walk_type): Don't error out on for_user option.
	(write_func_for_structure): Emit user marking routines if requested by
	for_user option.
	(write_local_func_for_structure): Likewise.
	(main): Mark types with for_user option as used.
	* ggc.h (gt_pch_nx): Add overload for unsigned int.
	* hash-map.h (hash_map::hash_entry::pch_nx_helper): AddOverloads.
	* hash-table.h (ggc_hasher): New struct.
	(hash_table::create_ggc): New function.
	(gt_pch_nx): New overload for hash_table.

java/

	* class.c, decl.c, except.c, expr.c, java-tree.h, lang.c: Use
	hash_table instead of hashtab.

objc/

	* objc-act.c: use hash_table instead of hashtab.

cp/

	* cp-gimplify.c, cp-tree.h, decl.c, mangle.c, name-lookup.c,
	pt.c, semantics.c, tree.c, typeck2.c: Use hash_table instead of
	hashtab.

fortran/

	* trans-decl.c, trans.c, trans.h: Use hash_table instead of hashtab.

c-family/

	* c-common.c: Use hash_table instead of hashtab.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@216127 138bc75d-0d04-0410-961f-82ee72b054a4