[testsuite] Require et alloca for Wstringop-overflow-3.c

2018-02-15  Tom de Vries  <tom@codesourcery.com>

	* gcc.dg/Wstringop-overflow-3.c: Require effective target alloca.

From-SVN: r257687

gcc/testsuite/ChangeLog

 2018-02-15  Tom de Vries  <tom@codesourcery.com>
 
+	* gcc.dg/Wstringop-overflow-3.c: Require effective target alloca.
+
+2018-02-15  Tom de Vries  <tom@codesourcery.com>
+
 	* gcc.c-torture/compile/pr84136.c: Require effective target
 	indirect_jumps.
 

gcc/testsuite/gcc.dg/Wstringop-overflow-3.c

 /* PR tree-optimization/84238 */
 /* { dg-do compile } */
 /* { dg-options "-O2" } */
+/* { dg-require-effective-target alloca } */
 
 char a[1];
 int b;