gcc:
	* doc/sourcebuild.texi (Effective-Target Keywords): Document
	run_expensive_tests.

	gcc/testsuite:
	* lib/target-supports.exp
	(check_effective_target_run_expensive_tests): New proc.
	* gcc.c-torture/compile/limits-fnargs.c: Use
	dg-require-effective-target run_expensive_tests.

From-SVN: r164012