Created attachment 248884 [details] add patch to FL/x.H In FL/x.H, the class Fl_XFont_On_Demand is not labelled FL_EXPORT which makes it not exposed in the library. It makes x11-toolkits/py-fltk fail on import as reported in the bug 277433. The patch fixes it. Reported upstream: https://github.com/fltk/fltk/issues/922