Make the Fortran front-end use garbage collection:

Make the Fortran front-end use garbage collection:

	* com.c (ffecom_init_0): Make double_ftype_double,
	float_ftype_float, ldouble_ftype_ldouble,
	ffecom_tree_ptr_to_fun_type_void local.
	(tracker_head): New static variable.
	(mark_tracker_head): New, marker procedure for tracker_head.
	(ffecom_save_tree_forever): New procedure.
	(ffecom_init_zero_): Remove obstack use.
	(ffecom_make_gfrt_): Remove obstack use.
	(ffecom_sym_transform_): Remove obstack use, save appropriate trees.
	(ffecom_transform_common_): Remove obstack use, save appropriate
	trees.
	(ffecom_type_namelist_): Remove obstack use, save appropriate
	trees.
	(ffecom_type_vardesc_): Remove obstack use, save appropriate trees.
	(ffecom_lookup_label): Remove obstack use, save appropriate trees.
	(duplicate_decls): Remove obstack use.
	(finish_function): push & pop ggc context around
	rest_of_compilation when building nested function.
	(mark_binding_level): New function.
	(init_decl_processing): Mark all the GC roots.
	(ggc_p): Set to 1.
	(lang_mark_tree): New function.
	(lang_mark_false_label_stack): New trivial function.
	* com.h (ffecom_save_tree_forever): Declare as external.
	* lex.c (ffelex_hash_): Use GC to allocate the filename string
	even when ffelex_kludge_flag_.
	* ste.c (ffeste_io_ialist_): Register a static root.
	(ffeste_io_inlist_): Likewise.
	(ffeste_io_icilist_): Likewise.
	(ffeste_io_cllist_): Likewise.
	(ffeste_io_cilist_): Likewise.
	(ffeste_io_olist_): Likewise.
	* Makefile.in (OBJS): Don't use ggc-callbacks.o.
	(OBJDEPS): Likewise.
	(GGC_H): New variable.
	Update dependencies.
	* where.c (ffewhere_head): New global.
	(mark_ffewhere_head): New marker procedure for ffewhere_head.
	(ffewhere_file_kill): Use GC to do memory management.
	(ffewhere_file_new): Use GC to do memory management.
	* ggc.j: New file.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@31142 138bc75d-0d04-0410-961f-82ee72b054a4