fix for thunderbird bustage from Bug 474743. (need <stdio.h> in new xpcshell test for 'printf' usage)

xpcom/tests/TestPriorityQueue.cpp

@@ -37,6 +37,7 @@
  * ***** END LICENSE BLOCK ***** */
 
 #include "nsTPriorityQueue.h"
+#include <stdio.h>
 #include <stdlib.h>
 
 template<class T, class Compare>