PR gcov-profile/36412
	* doc/gcov.texi: Document --hash-filenames(-x).
	* gcov.c (print_usage): Add the option.
	(process_args): Process the option, sort options alphabetically.
	(md5sum_to_hex): New function.
	(make_gcov_file_name): Do the md5sum and append it to a
	filename.

From-SVN: r239503