Implement a workaround to allow this test program to be compiled with clang.

It seems that if a pragma is used to define a weak alias for a local
function, the pragma must appear after the function is defined.

PR:		193056
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division

cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/pid/tst.weak2.c

@@ -34,14 +34,14 @@
  * leading underscores.
  */
 
-#pragma weak _go = go
-
 static int
 go(int a)
 {
 	return (a + 1);
 }
 
+#pragma weak _go = go
+
 static void
 handle(int sig)
 {