fontconfig: handle fallback corner cases
fontconfig: handle fallback corner cases

If no particular codepoint is requested (codepoint == 0), just return
the first font family. Additionally, handle fontconfig errors, albeit
they're unlikely to happen.

xbmc/libass,sanyaade-g2g-repos/libass,xbmc/libass,torque/libass,mwgoldsmith/libass,stps/libass,stps/libass,Akemi/libass,grigorig/libass,mwgoldsmith/libass,astiob/libass,Akemi/libass,ShiftMediaProject/libass,libass/libass,MrSmile/libass,torque/libass,stps/libass,libass/libass,sanyaade-g2g-repos/libass,ShiftMediaProject/libass,astiob/libass,grigorig/libass,MrSmile/libass,mwgoldsmith/libass,sanyaade-g2g-repos/libass,Akemi/libass,torque/libass