Debugger: Improve engine detection.

Try to detect engine by looking at toolchain, executable,
attach mode. Find out path to executable in attach to running
dialog.

Reviewed-by: hjk

src/plugins/debugger/debuggerplugin.h

@@ -125,7 +125,9 @@ private slots:
 private:
     void readSettings();
     void writeSettings() const;
-    void attachExternalApplication(qint64 pid, const QString &crashParameter = QString());
+    void attachExternalApplication(qint64 pid,
+                                   const QString &binary,
+                                   const QString &crashParameter);
     void attachCore(const QString &core, const QString &exeFileName);
 
     friend class Debugger::DebuggerManager;