Add a virtual dtor to wxEventLoopSourcesManagerBase to avoid g++ warnings.

This virtual dtor is not really needed as manager objects are static
singletons and are not destroyed via their pointer, but add a virtual dtor
just to avoid g++ warnings about its absence.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75666 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/private/eventloopsourcesmanager.h

@@ -13,13 +13,17 @@
 // For pulling in the value of wxUSE_EVENTLOOP_SOURCE
 #include "wx/evtloop.h"
 
+#if wxUSE_EVENTLOOP_SOURCE
+
 class WXDLLIMPEXP_BASE wxEventLoopSourcesManagerBase
 {
 public:
-#if wxUSE_EVENTLOOP_SOURCE
     virtual wxEventLoopSource*
     AddSourceForFD(int fd, wxEventLoopSourceHandler *handler, int flags) = 0;
-#endif
+
+    virtual ~wxEventLoopSourcesManagerBase() { }
 };
 
+#endif // wxUSE_EVENTLOOP_SOURCE
+
 #endif // _WX_PRIVATE_EVENTLOOPSOURCESMANAGER_H_