This is required since mmal_vout uses the fmod function.

This fixes loading of the mmal_vout plugin on raspbian.
Signed-off-by: Martin Storsjö <martin@martin.st>
(cherry picked from commit f389c750405ff2234a3f841801385e8dfb51c564)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>