MicroWindows (aka Nano-X) support hasn’t been updated since 2010 and last work for it in wxWidgets happened more than 10 years ago.
Run the genlang.py script from the top level wxWidgets directory to update include/wx/language.h (wxLanguage enum), interface/wx/language.h (its documentation) and src/common/languageinfo.cpp (conversion tables) with the data from langtabl.txt.