I don't think GBO_TO_CMD actually needs to do anything.
IMHO it maps the old options to the index of the group: ``` GEANY_GBO_COMPILE --> Index 0 in group GEANY_GBG_FT GEANY_GBO_BUILD --> Index 1 in group GEANY_GBG_FT GEANY_GBO_MAKE_ALL --> Index 2 in group GEANY_GBG_FT
GEANY_GBO_CUSTOM --> Index 0 in group GEANY_GBG_NON_FT GEANY_GBO_MAKE_OBJECT --> Index 1 in group GEANY_GBG_NON_FT
GEANY_GBO_EXEC --> Index 0 in group GEANY_GBG_EXEC ```