Document ov_open() unsafeness on win32 when dynamically linked.
Document ov_open() unsafeness on win32 when dynamically linked.

svn path=/trunk/vorbis/; revision=11210

mwgoldsmith/vorbis,mwgoldsmith/vorbis,ShiftMediaProject/vorbis,ksophocleous/vorbis,ShiftMediaProject/vorbis,felipebetancur/vorbis,erikd/vorbis,eidy/vorbis,ShiftMediaProject/vorbis,nicolaichuk/vorbis,eidy/vorbis,emscripten-ports/Vorbis,mwgoldsmith/vorbis,erikd/vorbis,emscripten-ports/Vorbis,ksophocleous/vorbis,erikd/vorbis,youfearm3/vorbis,youfearm3/vorbis,felipebetancur/vorbis,ksophocleous/vorbis,ShiftMediaProject/vorbis,nicolaichuk/vorbis,ksophocleous/vorbis,felipebetancur/vorbis,nicolaichuk/vorbis,youfearm3/vorbis,eidy/vorbis,emscripten-ports/Vorbis,ShiftMediaProject/vorbis,nicolaichuk/vorbis,erikd/vorbis,youfearm3/vorbis,mwgoldsmith/vorbis,felipebetancur/vorbis,emscripten-ports/Vorbis,eidy/vorbis,ShiftMediaProject/vorbis