* gcc.dg/cpp/include2a.c: Add comments to checks for multiple
	messages reported for one line of source code.
	* gcc.dg/cpp/pr30786.c: Likewise.
	* gcc.dg/cpp/pr28709.c: Likewise.
	* gcc.dg/cpp/missing-header-MD.c: Likewise.
	* gcc.dg/cpp/macspace2.c: Likewise.
	* gcc.dg/cpp/missing-header-1.c: Likewise.
	* gcc.dg/cpp/missing-header-MMD.c: Likewise.
	* gcc.dg/cpp/missing-sysheader-MD.c: Likewise.
	* gcc.dg/cpp/missing-sysheader-MMD.c: Likewise.

From-SVN: r188476