give the file name in the error message about failed Unicode conversion

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43802 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/textfile.cpp

@@ -132,7 +132,7 @@ bool wxTextFile::OnRead(const wxMBConv& conv)
 #if wxUSE_UNICODE
     if ( bufSize > 4 && str.empty() )
     {
-        wxLogError(_("Failed to convert file contents to Unicode."));
+        wxLogError(_("Failed to convert file \"%s\" to Unicode."), GetName());
         return false;
     }
 #endif // wxUSE_UNICODE