I just answered in the old topic - but it would make it very complicated if you had some tiles that you need to split again. I feel --gmapi converts everything - while --gmapi-minimal only converts input given in .o5m/osm.pbf/osm is the much better approach. The first time you use --gmapi - all subsequent times you use --gmapi-minimal. Otherwise it would not only need to be fine with asterisk, but also like reuse=<40000134.img
Sorry but I really don't see why any .img files should be converted again. Do it the first time you generate them - or just use --gmapi. I do not see the workflow where a reuse= whatever makes sense. While any o5m / osm / osm.pbf input would be strange to already exist as gmapi format but not as img format. Even more as mkgmap so far can use .img as input, but cannot use gmapi folders as input. If gmapi was possible as input as well - then your reuse list would make sense. But I do not have a use case for gmapi input.
And if gmapi input was possible then the correct approach would be to write the input like this:
123400??.img gmapi/123400?? 1234002?.o5m
In that case as we passed the map in img and gmapi format up to 19 as input - those shall not be written either as .img nor as gmapi.
However then
gmapi/123400?? 1234002?.05m would need to write out all .img files (overwrite those already present) and write the o5m files in both gmapi and img format. Mkgmap would then need to be able to convert into both directions and people who only need gmapi files would not need the .img files. So the call here should be - are there any people using mkgmap consistently and only need gmapi but not .img output? But I think that would be way too much work. Because so far mkgmap is simply converting to gmapi - not writing gmapi in first place from input data without writing .img files.