meson: building with opencv4 and auto_features=enabled fails

I only have opencv4 and building with -Dauto_features=enabled results in:

gst-libs/gst/opencv/meson.build:12:0: ERROR: Dependency "opencv" not found, tried pkgconfig

Relevant meson logic: https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/blob/3a5bcfc59310b7093f828e902883314623d60662/gst-libs/gst/opencv/meson.build#L12

Auto preferring opencv3 over 4 also seems fishy (are they parallel installable?). Maybe there needs to be a build option for selecting the major version to search for?