[committed] Avoid undefined behavior in test.

[Alexander Monakov]

I have committed the following testsuite patch as obvious.

The test calls a variadic function that extracts pointers with va_arg, but the
terminating NULL is passed as an int, not a pointer.  This wouldn't trip on
32-bit architectures, and even on 64-bit the test simply iterates until it
gets a NULL stack slot (in any containing frame).

Noticed while testing NVPTX with -mgomp.

2015-12-09  Alexander Monakov  <amona...@ispras.ru>

        * gcc.c-torture/execute/980716-1.c: Avoid undefined behavior due to
        passing terminating NULL as int rather than pointer.

--- gcc.c-torture/execute/980716-1.c    (revision 231457)
+++ gcc.c-torture/execute/980716-1.c    (working copy)
@@ -20,7 +20,7 @@
 int
 main()
 {
-    stub(1, "ab", "bc", "cx", 0);
+    stub(1, "ab", "bc", "cx", (char *)0);
     exit (0);
 }