USE_SUB was hardcoded to true in configure, manually turning it off
would break compilation, and there's no apparent reason why having all
subtitle code under #ifdefs (even working ones) would be worth the
clutter.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@21156 b3059339-0415-0410-9bf9-f77b7e298cf2