Fix renaming of classes in Windows (OpenModelica#12594)

Fixes OpenModelica#12567

OMEdit/OMEditLIB/Modeling/LibraryTreeWidget.cpp

@@ -4694,6 +4694,15 @@ bool LibraryWidget::saveFile(QString fileName, QString contents)
     default:
       break;
   }
+  /* Issue #12567
+   * Try to remove the file if it already exists since Windows can't handle case sensitive file names.
+   * So if we already have `a.mo` and wants to save it as `A.mo` then the file is saved with new contents but the filename remains `a.mo`
+   */
+#ifdef Q_OS_WIN
+  if (QFile::exists(fileName)) {
+    QFile::remove(fileName);
+  }
+#endif
   // open the file for writing
   QFile file(fileName);
   if (file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
@@ -5096,7 +5105,12 @@ bool LibraryWidget::saveModelicaLibraryTreeItemFolder(LibraryTreeItem *pLibraryT
       QString currentLine = textStream.readLine();
       bool classExists = false;
       for (int i = 0; i < pLibraryTreeItem->childrenSize(); i++) {
+        // Issue #12567. Compare case insensitive on Windows as `a` and `A` means the same thing.
+#ifdef Q_OS_WIN
+        if (pLibraryTreeItem->child(i)->getName().compare(currentLine, Qt::CaseInsensitive) == 0) {
+#else // #ifdef Q_OS_WIN
         if (pLibraryTreeItem->child(i)->getName().compare(currentLine) == 0) {
+#endif // #ifdef Q_OS_WIN
           classExists = true;
           break;
         }