doc/sourcebuild.texi (Selectors): Document the use of target and xfail used together.

doc/sourcebuild.texi (Selectors): Document the use of target and xfail used together.

	doc/sourcebuild.texi (Selectors): Document the use of target
	and xfail used together.
testsuite/
	* lib/target-supports-dg.exp (dg-require-effective-target,
	dg-skip-if, dg-xfail-if, dg-xfail-run-if, dg-shouldfail): Call
	dg-process-target-1 instead of dg-process-target.
	(dg-process-target-1): Rename from dg-process-target.
	(dg-process-target): New.

From-SVN: r191670