Debug stub: suspend/resume threads on Linux

src/trusted/port/thread.h

Index: src/trusted/port/thread.h
diff --git a/src/trusted/port/thread.h b/src/trusted/port/thread.h
index eed194bb80865c7d78c38cf2e2b160c2cc6f2f05..32c235b7d5c59cc134c2646219a0f9aaebf472f2 100644
--- a/src/trusted/port/thread.h
+++ b/src/trusted/port/thread.h
@@ -57,6 +57,9 @@ class IThread {
   static void Release(IThread *thread);
   static void SetExceptionCatch(CatchFunc_t func, void *cookie);
 
+  static void SuspendAll(uint32_t signaled_id);
+  static void ResumeAll(uint32_t signaled_id);
+
  protected:
   virtual ~IThread() {}  // Prevent delete of base pointer
 };