Case insensitive comparison for file extensions in two places...

... consistent with handling of file extensions elsewhere

src/DirManager.cpp

@@ -2124,8 +2124,8 @@ void DirManager::FindOrphanBlockFiles(
       if ((mBlockFileHash.find(basename) == mBlockFileHash.end()) && // is orphan
             // Consider only Audacity data files.
             // Specifically, ignore <branding> JPG and <import> OGG ("Save Compressed Copy").
-            (ext.IsSameAs(wxT("au")) ||
-               ext.IsSameAs(wxT("auf"))))
+            (ext.IsSameAs(wxT("au"), false) ||
+               ext.IsSameAs(wxT("auf"), false)))
       {
          if (!clipboardDM) {
             TrackList *clipTracks = AudacityProject::GetClipboardTracks();

src/PluginManager.cpp

@@ -1791,8 +1791,8 @@ bool PluginManager::DropFile(const wxString &fileName)
 
       const auto &ff = module->InstallPath();
       auto extensions = module->GetFileExtensions();
-      if (!ff.empty() &&
-          make_iterator_range(extensions).contains(src.GetExt())) {
+      if ( !ff.empty() &&
+          extensions.Index(src.GetExt(), false) != wxNOT_FOUND ) {
          wxString errMsg;
          // Do dry-run test of the file format
          unsigned nPlugIns =