meson: Disabling some plugins leads to build failures

For instance, rav1e:

$ meson setup build -Drav1e=disabled
$ meson compile -C build
INFO: autodetecting backend as ninja
INFO: calculating backend command to run: /usr/bin/ninja -C /var/home/phil/dev/rust/gst-plugins-rs/build
ninja: Entering directory `/var/home/phil/dev/rust/gst-plugins-rs/build'
[0/3] Generating gst-plugins-rs with a custom command (wrapped by meson to set env)
    Skipping git submodule `https://github.com/gtk-rs/gir` due to update strategy in .gitmodules
    Skipping git submodule `https://github.com/gtk-rs/gir-files` due to update strategy in .gitmodules
    Skipping git submodule `https://gitlab.freedesktop.org/gstreamer/gir-files-rs.git` due to update strategy in .gitmodules
    Skipping git submodule `https://github.com/gtk-rs/gir` due to update strategy in .gitmodules
    Skipping git submodule `https://github.com/gtk-rs/gir-files` due to update strategy in .gitmodules
    Skipping git submodule `https://github.com/gtk-rs/gir` due to update strategy in .gitmodules
    Skipping git submodule `https://github.com/gtk-rs/gir-files` due to update strategy in .gitmodules
Error: CliError { error: Some(none of the selected packages contains these features: gst-plugin-rav1e/asm, did you mean: gst-plugin-dav1d/capi, gst-plugin-dav1d/doc, gst-plugin-ffv1/capi, gst-plugin-ffv1/doc?), exit_code: 101 }
FAILED: libgstrsaudiofx.so libgstclaxon.so libgstlewton.so libgstspotify.so libgstrsfile.so libgstthreadshare.so libgstmp4.so libgstfmp4.so libgstaws.so libgsthlssink3.so libgstndi.so libgstrsonvif.so libgstraptorq.so libgstreqwest.so libgstrsrtp.so libgstwebrtchttp.so libgstrswebrtc.so libgsttextahead.so libgstjson.so libgstregex.so libgsttextwrap.so libgstfallbackswitch.so libgstlivesync.so libgsttogglerecord.so libgstrstracers.so libgsturiplaylistbin.so libgstcdg.so libgstrsclosedcaption.so libgstdav1d.so libgstffv1.so libgstrsflv.so libgstgif.so libgsthsv.so libgstrspng.so libgstrsvideofx.so libgstrswebp.so libgstsodium.so libgstgtk4.so 
env PKG_CONFIG_PATH=/var/home/phil/gstreamer/build/meson-uninstalled:/var/home/phil/gstreamer/prefix/lib/pkgconfig /usr/bin/python3 /var/home/phil/dev/rust/gst-plugins-rs/cargo_wrapper.py build /var/home/phil/dev/rust/gst-plugins-rs/build /var/home/phil/dev/rust/gst-plugins-rs /var/home/phil/dev/rust/gst-plugins-rs/build debug /usr/local lib64 --packages gst-plugin-audiofx gst-plugin-claxon gst-plugin-lewton gst-plugin-spotify gst-plugin-file gst-plugin-threadshare gst-plugin-mp4 gst-plugin-fmp4 gst-plugin-aws gst-plugin-hlssink3 gst-plugin-ndi gst-plugin-onvif gst-plugin-raptorq gst-plugin-reqwest gst-plugin-rtp gst-plugin-webrtchttp gst-plugin-webrtc gst-plugin-textahead gst-plugin-json gst-plugin-regex gst-plugin-textwrap gst-plugin-fallbackswitch gst-plugin-livesync gst-plugin-togglerecord gst-plugin-tracers gst-plugin-uriplaylistbin gst-plugin-cdg gst-plugin-closedcaption gst-plugin-dav1d gst-plugin-ffv1 gst-plugin-flavors gst-plugin-gif gst-plugin-hsv gst-plugin-png gst-plugin-videofx gst-plugin-webp gst-plugin-sodium gst-plugin-gtk4 --features glib/v2_74 gio/v2_74 gst/v1_22 gst-app/v1_22 gst-audio/v1_22 gst-base/v1_22 gst-check/v1_22 gst-net/v1_22 gst-pbutils/v1_22 gst-plugin-tracers/v1_22 gst-rtp/v1_22 gst-sdp/v1_22 gst-utils/v1_22 gst-video/v1_22 gst-webrtc/v1_22 gst-plugin-webrtc/gst1_22 gst-plugin-rav1e/asm gtk gio gst-plugin-gtk4 gtk gio gst-plugin-gtk4 gtk gio gst-plugin-gtk4 clap serde serde_json clap wayland x11egl x11glx --depfile gst-plugins-rs.dep --lib-suffixes so
ninja: build stopped: subcommand failed.