gdb/

gdb/
	Code cleanup.
	* charset.c (find_charset_names): Remove variables ix and elt.
	Use free_char_ptr_vec.
	* elfread.c (build_id_to_debug_filename): New variables debugdir_vec,
	back_to and ix.  Use dirnames_to_char_ptr_vec.  Remove variable
	debugdir_end.  New variable debugdir_len.
	* gdb_vecs.h (free_char_ptr_vec, make_cleanup_free_char_ptr_vec)
	(dirnames_to_char_ptr_vec_append, dirnames_to_char_ptr_vec): New
	declarations.
	* progspace.c (clear_program_space_solib_cache): Remove variables ix
	and elt.  Use free_char_ptr_vec.
	* source.c (add_path): Remove variables argv, arg and argv_index.
	New variables dir_vec, back_to, ix and name.
	Use dirnames_to_char_ptr_vec_append.  Use freeargv instead of
	make_cleanup_freeargv.  Remove variable separator.  Simplify the code
	no longer expecting DIRNAME_SEPARATOR.
	(openp): Remove variable p, p1 and len.  New variables dir_vec,
	back_to, ix and dir.  Use dirnames_to_char_ptr_vec.  Simplify the code
	no longer expecting DIRNAME_SEPARATOR.
	* symfile.c (find_separate_debug_file): New variables debugdir_vec,
	back_to and ix.  Use dirnames_to_char_ptr_vec.  Remove variable
	debugdir_end.
	* utils.c (free_char_ptr_vec, do_free_char_ptr_vec)
	(make_cleanup_free_char_ptr_vec, dirnames_to_char_ptr_vec_append)
	(dirnames_to_char_ptr_vec): New functions.