PR testsuite/20771
	* lib/dg-pch.exp: Move a flag in arguments to dg-test to differentiate
	compile results for pch test lines in gcc.sum.
	* gcc.dg/pch/counter-2.c: Add comments to dg-error directives to
	make them unique in gcc.sum.
	* gcc.dg/pch/valid-1.c: Ditto.
	* gcc.dg/pch/valid-2.c: Ditto.
	* gcc.dg/pch/valid-3.c: Ditto.
	* gcc.dg/pch/warn-1.c: Same for dg-warning.

From-SVN: r135696