[ARM,testsuite] Make arm_arch_FUNC_ok more robust

2018-01-18  Christophe Lyon <christophe.lyon@linaro.org>

	* lib/target-supports.exp (check_effective_target_arm_arch_FUNC_ok):
	Add function body to force error messages in some configurations.

From-SVN: r256849

gcc/testsuite/ChangeLog

+2018-01-18  Christophe Lyon <christophe.lyon@linaro.org>
+
+	* lib/target-supports.exp (check_effective_target_arm_arch_FUNC_ok):
+	Add function body to force error messages in some configurations.
+
 2018-01-18  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/arm/pr70278.c: Add effective target checks for armv4t

gcc/testsuite/lib/target-supports.exp

@@ -4125,6 +4125,11 @@ foreach { armfunc armflag armdefs } {
 		#if !(DEFS)
 		#error !(DEFS)
 		#endif
+		int
+		main (void)
+		{
+		    return 0;
+		}
 	    } "FLAG" ]
 	}