Improve cppcheck configuration

- Ignore autotests sources
- Teach cppcheck about a okular specific define
- Keep the default options from the KDE setup

This at least for me brings the cppcheck entries from "unusable" to "something that probably should be looked into"

.kde-ci.yml

@@ -27,3 +27,8 @@ Dependencies:
 - 'on': ['Android']
   'require':
     'frameworks/kirigami': '@stable'
+
+Options:
+  cppcheck-arguments: '--enable=warning,style,performance -DOKULAR_EXPORT_PLUGIN'
+  cppcheck-ignore-files:
+    - autotests

shell/welcomescreen.cpp

@@ -41,10 +41,10 @@ public:
         const RecentItemsModel *model = static_cast<RecentItemsModel *>(aModel);
         const RecentItemsModel::RecentItem *item = model->getItem(index);
 
-        bool willOpenMenu = false;
         QPoint menuPosition;
 
         if (item != nullptr) {
+            bool willOpenMenu = false;
             if (event->type() == QEvent::ContextMenu) {
                 willOpenMenu = true;
                 menuPosition = static_cast<QContextMenuEvent *>(event)->globalPos();