ass_fontselect: do not use PATH_MAX
ass_fontselect: do not use PATH_MAX

This seems to cause issues on MSVC. Considering that even most Unix OSes
hate PATH_MAX and don't really honour it, using 4096 is just as good.

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