Implement -fprofile-prefix-map.

Implement -fprofile-prefix-map.

	PR gcov-profile/96092

gcc/ChangeLog:

	* common.opt: New option.
	* coverage.c (coverage_begin_function): Emit filename with
	remap_profile_filename.
	* doc/invoke.texi: Document the new option.
	* file-prefix-map.c (add_profile_prefix_map): New.
	(remap_profile_filename): Likewise.
	* file-prefix-map.h (add_profile_prefix_map): Likewise.
	(remap_profile_filename): Likewise.
	* lto-opts.c (lto_write_options): Handle
	OPT_fprofile_prefix_map_.
	* opts-global.c (handle_common_deferred_options): Likewise.
	* opts.c (common_handle_option): Likewise.
	(gen_command_line_string): Likewise.
	* profile.c (output_location): Emit filename with
	remap_profile_filename.