+ Add missing include

Signed-off-by: Jean-Philippe André <jpeg@videolan.org>

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

This decoder will try to use OpenMAX IL components to decode video/audio.
Only 2 OpenMAX cores are currently looked for. The TI OMAP IL core (used for
instance on the N900) and the Bellagio IL core.
This decoder is disabled by default (use --enable-omxil) and for now has
a zero priority (use --codec omxil).

P.S.: I don't like to include VLC headers in plugin-wide headers

That said, if someone really wants to support running vlc.exe from the
build tree, this is far from sufficient. I would suggest setting
data-path and plugin-path in static compilations of winvlc.c like we
already do for vlc.c instead.