header name: [libgen.h](https://pubs.opengroup.org/onlinepubs/7908799/xsh/libgen.h.html) required by: [flex](https://github.com/westes/flex) required function(s): [basename](https://github.com/westes/flex/blob/535524ea6b55f8f6a7dfc160cb19211c084795d6/src/main.c#L999)
