ensure that we have event loop before showing a modal dialog; this allows to do it even before the main application loop starts

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61269 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/carbon/dialog.cpp

@@ -47,17 +47,10 @@ void wxDialog::DoShowModal()
     }
     BeginAppModalStateForWindow(windowRef) ;
 
-    wxEventLoop * const
-        loop = static_cast<wxEventLoop *>(wxEventLoop::GetActive());
-
-
-    wxASSERT_MSG( loop , wxT("No Event Loop in place") );
-
-    if ( loop )
-    {
+    wxEventLoopGuarantor ensureHasLoop;
+    wxEventLoopBase * const loop = wxEventLoop::GetActive();
     while ( IsModal() )
         loop->Dispatch();
-    }
 
     EndAppModalStateForWindow(windowRef) ;
     if ( resetGroupParent )