Add the "- waiting on"/"- waiting to lock" lines to the SIGQUIT output.

Change-Id: I0a8ab2e9e54c390e0d499ef464d82c2f2c628cbe
diff --git a/src/monitor.h b/src/monitor.h
index 8c22fb1..fefc43e 100644
--- a/src/monitor.h
+++ b/src/monitor.h
@@ -20,6 +20,8 @@
 #include <pthread.h>
 #include <stdint.h>
 
+#include <iosfwd>
+
 #include "mutex.h"
 
 namespace art {
@@ -71,6 +73,8 @@
 
   static void FreeMonitorList();
 
+  static void DescribeWait(std::ostream& os, const Thread* thread);
+
  private:
   Monitor(Object* obj);