Store include-from as a location, not line-map index.

Store include-from as a location, not line-map index.

	libcpp/
	* include/line-map.h (line_map_ordinary): Replace included_from
	index with included_at source_location.
	(ORDINARY_MAP_INCLUDER_FILE_INDEX, LAST_SOURCE_LINE_LOCATION)
	(LAST_SOURCE_LINE, LAST_SOURCE_COLUMN): Delete.
	(INCUDED_FROM): Delete.
	(INCLUDED_AT, linemap_included_at): New.
	(MAIN_FILE_P): Adjust.
	* directives.c (do_linemarker): Use linemap_included_at.
	* line-map.c (include_at_map): New.
	(line_check_files_exited): Use it.
	(LAST_SOURCE_LINE_LOCATION): New (moved from header).
	(linemap_add, linemap_dump, linemap_dump_location): Adjust.
	gcc/
	* diagnostic.c (diagnostic_report_current_module): Use
	linemap_included_at.  Adjust line & col discovery.
	gcc/c-family/
	* c-common.c (try_to_locate_new_include_insertion_point): Use
	linemap_included_at.
	* c-lex.c (fe_file_change): Use INCLUDED_AT.
	* c-ppoutput.c (pp_file_change): Likewise.
	gcc/fortran/
	* cpp.c (cb_file_change): Adjust for line map inclusion changes.

From-SVN: r262553