re PR preprocessor/36649 (-H option doesn't work as expected)

	PR preprocessor/36649
	* files.c (struct report_missing_guard_data): New type.
	(report_missing_guard): Put paths into an array instead of printing
	them right away.  Return 1 rather than 0.
	(report_missing_guard_cmp): New function.
	(_cpp_report_missing_guards): Sort and print paths gathered by
	report_missing_guard callback.

	* gcc.dg/pch/cpp-3.hs: Add include guards.
	* gcc.dg/pch/cpp-3a.h: Likewise.
	* gcc.dg/pch/cpp-3b.h: Likewise.
	* gcc.dg/cpp/mi8.c: New test.
	* gcc.dg/cpp/mi8a.h: New file.
	* gcc.dg/cpp/mi8b.h: New file.
	* gcc.dg/cpp/mi8c.h: New file.
	* gcc.dg/cpp/mi8d.h: New file.

From-SVN: r138432