debugger: don't retrieve the stack if we know we will continue stepping

src/plugins/debugger/gdb/gdbengine.h

@@ -284,6 +284,7 @@ private: ////////// Gdb Output, State & Capability Handling //////////
     void handleStop0(const GdbMi &data);
     void handleStop1(const GdbResponse &response);
     void handleStop1(const GdbMi &data);
+    Q_SLOT void handleStop2();
     StackFrame parseStackFrame(const GdbMi &mi, int level);
     void resetCommandQueue();
 
@@ -537,6 +538,10 @@ private: ////////// View & Data Stuff //////////
     QString m_toolTipExpression;
     QPoint m_toolTipPos;
 
+    // For short-circuiting stack and thread list evaluation.
+    bool m_stackNeeded;
+    int m_currentThreadId;
+
     // HACK:
     StackFrame m_targetFrame;
 };