* configure.in (CHECK_SUBDIRS): Set to testsuite only if
	${srcdir}/../gcc exists.
	(configdirs): Include testsuite only if ${srcdir}/../gcc exists.
	* tests/Makefile.in (check): Depend on $(CHECK).
	* tests/configure.in (CHECK): Set to "check-iostream
	check-stdio" if ${srcdir}/../../gcc doesn't exists.

From-SVN: r17336