Fix the decoding of DW_FORM_ref_addr DWARF attribute.

Fix the decoding of DW_FORM_ref_addr DWARF attribute.

	* dwarf.c (struct abbrev_list): New structure.  Used to collect
	lists of abbreviation sets.
	(struct abbrev_map): New structure.  Used to map CU offsets to
	abbreviation offsets.
	(record_abbrev_list): New function.  A new entry to an
	abbreviation list.
	(free_all_abbrevs): Update to free abbreviation lists.
	(new_abbrev_list): New function.  Start a new abbreviation
	list.
	(find_abbrev_list_by_abbrev_offset): New function.
	(find_abbrev_map_by_offset): New function.
	(add_abbrev): Add abbrev_list parameter.
	(add_abbrev_attr): Likewise.
	(process_abbrev_section): Rename to process_abbrev_set and add
	list parameter.
	(get_type_abbrev_from_form): New function.  Attempts to decode the
	forms used by DW_AT_type attributes.
	(get_type_signedness): Display type names if operating in wide
	mode.  Use get_type_abbrev_from_form.
	(read_and_display_attr_value): Use get_type_abbrev_from_form.
	(process_debug_info): Pre-parse the CU headers to collate all the
	abbrevs before starting the main scan.
	(process_debug_abbrev): Do not free any loaded abbrevs.
	(free_debug_memory): Free the abbrev maps.