Undefined members of structures lead to huge export file sizes (e.g. xml)

[gynt]

Is your feature request related to a problem? Please describe.
Large XML files, e.g. 3GB while the program is only 8MB, are caused in my case by the XML exporter writing many members of structures that are of datatype undefined. In my case, I know many of the sizes of structures, but I haven't documented all members yet. Likely, many of the undefined will turn about to be long arrays. Exporting "Data" is not really feasible this way.

Describe the solution you'd like
I would like the option in the XML exporter to ignore undefined members of structures. Since every member also has an offset, I think this is no problem.

Describe alternatives you've considered
Post-processing of the xml file. But then that means I would need to read in the file. The quick and dirty solution right now is to remove all lines in the xml file containing DATATYPE="undefined".

Additional context
NA