test-long-names.c: Fix build with -Wformat-security.

2018-11-26  Matthias Klose  <doko@ubuntu.com>

        * jit.dg/test-long-names.c: Fix build with -Wformat-security.

From-SVN: r266454

gcc/testsuite/ChangeLog

+2018-11-26  Matthias Klose  <doko@ubuntu.com>
+
+	* jit.dg/test-long-names.c: Fix build with -Wformat-security.
+
 2018-11-25  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* lib/target-supports.exp (check_compile): Handle D.

gcc/testsuite/jit.dg/test-long-names.c

@@ -24,7 +24,7 @@ populate_name (const char *prefix, char *buffer)
   int i;
 
   /* Begin with the given prefix: */
-  sprintf (buffer, prefix);
+  sprintf (buffer, "%s", prefix);
 
   /* Populate the rest of the buffer with 0123456789 repeatedly: */
   for (i = strlen (prefix); i < NAME_LENGTH - 1; i++)