meson: fix build failure if orc is enabled but none of its users are
Potential fix for #778 (closed), where meson configure fails if orc
is enabled but audiofx
, deinterlace
, videobox
, and videomixer
are all disabled.
Potential fix for #778 (closed), where meson configure fails if orc
is enabled but audiofx
, deinterlace
, videobox
, and videomixer
are all disabled.