[testsuite] gcc.dg/nextafter-2.c: Restrict to c99_runtime

2018-05-07  Christophe Lyon  <christophe.lyon@linaro.org>

	* gcc.dg/nextafter-2.c: Add c99_runtime effective target
	and options.

From-SVN: r259994

gcc/testsuite/ChangeLog

+2018-05-07  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	* gcc.dg/nextafter-2.c: Add c99_runtime effective target
+	and options.
+
 2018-05-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/85659

gcc/testsuite/gcc.dg/nextafter-2.c

 /* PR libstdc++/85466 */
 /* { dg-do run } */
+/* { dg-require-effective-target c99_runtime } */
 /* { dg-options "-O2 -fno-builtin" } */
 /* { dg-add-options ieee } */
+/* { dg-add-options c99_runtime } */
 
 #include "nextafter-1.c"