Fix bugs in wxEnumProperty introduced by r76562.

The compilation fixes introduced run-time fixes due to not account for the use
of NULL pointers (which are not accepted as choices cache but are accepted as
choices values, go figure).

Closes #16266.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76569 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/propgrid/props.cpp

@@ -1130,9 +1130,10 @@ wxEnumProperty::wxEnumProperty( const wxString& label, const wxString& name,
     }
     else
     {
-        for ( ; untranslatedLabels; untranslatedLabels++, values++ )
+        for ( int i = 0; *untranslatedLabels; untranslatedLabels++ )
         {
-            m_choices.Add(wxGetTranslation(*untranslatedLabels), *values);
+            const long val = values ? *values++ : i++;
+            m_choices.Add(wxGetTranslation(*untranslatedLabels), val);
         }
 
         if ( GetItemCount() )