Fix compilation without fontconfig
Fix compilation without fontconfig

Conditionally add the fontconfig provider. We can actually run
without fontconfig now! That is, if embedded fonts or fallbacks are
good enough.

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