gcov: emit hotness colors to easily find hot code.

gcov: emit hotness colors to easily find hot code.

2018-09-17  Martin Liska  <mliska@suse.cz>

	* doc/gcov.texi: Document new option --use-hotness-colors.
	* gcov.c (struct source_info): Declare new field.
	(source_info::source_info): Set default for maximum_count.
	(print_usage): Add new -q option.
	(process_args): Process it.
	(accumulate_line_info): Save src->maximum_count.
	(output_line_beginning): Make color line number if
	flag_use_hotness_colors is set.
	(output_line_details): Pass default argument value.
	(output_lines): Pass src->maximum_count.

From-SVN: r264360