Please, update mplayer ebuild to support modular xorg install if dga useflag is enabled. Follow a patch against mplayer 1.0_pre7-r1 Thanks
Created attachment 71783 [details, diff] patch for modular xorg against mplayer-1.0_pre7-r1.ebuild
It ended up being a fair bit more significant than that, because of the X based dependencies being conditional on any of gtk, X, xinerama or xv (same as --enable-x11 is).