Re-add mysteriously missing connections for custom env variables checkbox

- Probably removed during QtDesigner changes to .ui file; code into .cpp file instead
- Possible fix for #6961

Author: dakcarto

src/app/qgsoptions.cpp

@@ -1365,6 +1365,13 @@ QStringList QgsOptions::i18nList()
   return myList;
 }
 
+void QgsOptions::on_mCustomVariablesChkBx_toggled( bool chkd )
+{
+  mAddCustomVarBtn->setEnabled( chkd );
+  mRemoveCustomVarBtn->setEnabled( chkd );
+  mCustomVariablesTable->setEnabled( chkd );
+}
+
 void QgsOptions::addCustomEnvVarRow( QString varName, QString varVal, QString varApply )
 {
   int rowCnt = mCustomVariablesTable->rowCount();

src/app/qgsoptions.h

@@ -117,6 +117,11 @@ class QgsOptions : public QDialog, private Ui::QgsOptionsBase
     /**Remove an URL to exclude from Proxy*/
     void on_mRemoveUrlPushButton_clicked();
 
+    /** Slot to enable custom environment variables table and buttons
+     * @note added in QGIS 1.9
+     */
+    void on_mCustomVariablesChkBx_toggled( bool chkd );
+
     /** Slot to add a custom environment variable to the app
      * @note added in QGIS 1.9
      */