PR preprocessor/83173: Enhance -fdump-internal-locations output

PR preprocessor/83173: Enhance -fdump-internal-locations output

gcc/ChangeLog:
2018-11-27  Mike Gulick  <mgulick@mathworks.com>

	PR preprocessor/83173
	* input.c (dump_location_info): Dump reason and included_from
	fields from line_map_ordinary struct.  Fix indentation when
	location > 5 digits.
	* diagnostic-show-locus.c (num_digits, num_digits): Move to
	diagnostic.c to allow it to be utilized by input.c.
	* diagnostic.c (num_digits, selftest::test_num_digits): Moved
	here.
	(selftest::diagnostic_c_tests): Run selftest::test_num_digits.
	* diagnostic.h (num_digits): Add extern definition.

libcpp/ChangeLog:
2018-11-27  Mike Gulick  <mgulick@mathworks.com>

	PR preprocessor/83173
	* location-example.txt: Update example -fdump-internal-locations
	output.

From-SVN: r266520