The <ctype.h> frontend is complete, the backend currently only supporting "C" locale / ASCII-7. (This will change before v0.6 gets released. I intend to at least fully cover ISO-8859-1 through -16 by then, but I need the loading / saving code before I add locales.)
localeconv() was a no-brainer.
When I got to setlocale(), I realized I was pretty fed up with C coding for the time being, and put the project on the backburner (occassional bugfixes notwithstanding, Rink is really hammering my poor ol' PDCLib with his porting projects

Currently, I'm working on a pen & paper FRPG project I've been aching to do for quite some time. Once that is done, I'll continue with PDCLib "full time".