* c-ppoutput.c (pp_dir_change): New function.
* c-common.h (pp_dir_change): New declaration.
* cpplib.h (struct cpp_options): Remove working_directory field.
* cppinit.c (cpp_find_main_file, cpp_push_main_file): Merge back to
(cpp_read_main_file): as before 10-01. Call _cpp_stack_file.
Don't handle -fworking_directory here, but in c_common_post_options.
(read_original_directory): Don't back up when done.
Don't clear no-longer used working_directory flag.
* cpplib.h: Update declarations to match.
* c-lex.c (cb_dir_change): Move to c-opts.c.
(init_c_lex): Don't set dir_change callback here, since we want
to set it even if flag_preprocess_only.
* c-opts.c (cb_dir_change): Function moved from c-lex.c.
(c_common_post_options): Set dir_change callback.
Call pp_dir_change if approporiate.
(finish_options): Don't call cpp_find_main_file here. Hence remove
unneeded parameter and result. Do LC_RENAME for <built-in>.
(c_common_post_options): Call cpp_read_main_file here instead.
(c_common_init): Update accordingly.
(push_command_line_include): Don't cpp_push_main_file.
Do LC_RENAME rather than LC_LEASE to get back to main file.
Compared to pre-10-01 version, inline cpp_rename_to_main_file.
(c_common_parse_file): Call cpp_read_main_file for subsequent main
files, but call finish_options for all files.
* c-opts.c (sanitize_cpp_opts): Don't set cpp_opts->working_directory.
* fix-header.c (read_scan_file): Call cpp_read_main_file instead of
cpp_find_main_file + cpp_push_main_file.
* c-lex.c (fe_file_change): Don't set main_input_filename here.
* opts.c (handle_options): Only set main_input_filename first time.