debugger: simplify the 'break at main' logic

src/plugins/debugger/debuggerengine.h

@@ -76,7 +76,6 @@ public:
     QString workingDirectory;
     qint64 attachPID;
     bool useTerminal;
-    bool breakAtMain;
 
     // Used by AttachCrashedExternal.
     QString crashParameter;
@@ -257,9 +256,6 @@ public:
     bool debuggerActionsEnabled() const;
     static bool debuggerActionsEnabled(DebuggerState state);
 
-    void breakByFunction(const QString &functionName);
-    void breakByFunctionMain();
-
     DebuggerState state() const;
     DebuggerState lastGoodState() const;
     DebuggerState targetState() const;