Fix generation of libass.pc
Fix generation of libass.pc

mwgoldsmith/libass,tgoyne/libass,sanyaade-g2g-repos/libass,stps/libass,astiob/libass,grigorig/libass,xbmc/libass,pigoz/libass-ct,pigoz/libass-ct,libass/libass,pigoz/libass-ct,tgoyne/libass,libass/libass,blinkseb/libass,ShiftMediaProject/libass,mwgoldsmith/libass,sanyaade-g2g-repos/libass,stps/libass,Akemi/libass,sanyaade-g2g-repos/libass,grigorig/libass,blinkseb/libass,richardpl/libass,xbmc/libass,ShiftMediaProject/libass,blinkseb/libass,MrSmile/libass,tgoyne/libass,richardpl/libass,MrSmile/libass,astiob/libass,mwgoldsmith/libass,stps/libass,richardpl/libass,Akemi/libass,torque/libass,Akemi/libass,torque/libass,torque/libass