[media-kit] media-libs/mlt-7.40.0 several failures

Nobody has claimed this yet.

`USE="ffmpeg jack sdl vorbis -frei0r -gdk -opencv -qt6 -rtaudio -sox"` produces
```
-- Configuring done (2.8s)
CMake Error in src/modules/jackrack/CMakeLists.txt:
Imported target "PkgConfig::lilv" includes non-existent path

"/usr/include/lilv-0"

in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include:

* The path was deleted, renamed, or moved to another location.

* An install or uninstall procedure did not complete successfully.

* The installation package was faulty and references files it does not
provide.
```

`media-libs/lilv` needs to be fixed and autogenned

then

```
[180/303] /usr/bin/x86_64-pc-linux-gnu-gcc -DGPL -DWITH_LV2 -DWITH_VST2 -Dmltladspa_EXPORTS -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0_build/src/modules/jackrack -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/framework/.. -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0_build/src/framework -isystem /usr/include/libxml2 -isystem /usr/include/glib-2.0 -isystem /usr/lib64/glib-2.0/include -isystem /usr/include/sratom-0 -isystem /usr/include/sord-0 -isystem /usr/include/serd-0 -mtune=generic -O2 -pipe -std=gnu11 -fPIC -mmmx -msse -msse2 -MD -MT src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o -MF src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o.d -o src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o -c /var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/modules/jackrack/plugin_mgr.c
FAILED: [code=1] src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o
/usr/bin/x86_64-pc-linux-gnu-gcc -DGPL -DWITH_LV2 -DWITH_VST2 -Dmltladspa_EXPORTS -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0_build/src/modules/jackrack -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/framework/.. -I/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0_build/src/framework -isystem /usr/include/libxml2 -isystem /usr/include/glib-2.0 -isystem /usr/lib64/glib-2.0/include -isystem /usr/include/sratom-0 -isystem /usr/include/sord-0 -isystem /usr/include/serd-0 -mtune=generic -O2 -pipe -std=gnu11 -fPIC -mmmx -msse -msse2 -MD -MT src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o -MF src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o.d -o src/modules/jackrack/CMakeFiles/mltladspa.dir/plugin_mgr.c.o -c /var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/modules/jackrack/plugin_mgr.c
/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/modules/jackrack/plugin_mgr.c: In function ‘lv2_mgr_new’:
/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/modules/jackrack/plugin_mgr.c:568:53: error: ‘LV2_UI__scaleFactor’ undeclared (first use in this function); did you mean ‘urid_ui_scaleFactor’?
568 | urid_ui_scaleFactor = uri_table_map(&uri_table, LV2_UI__scaleFactor);
| ^~~~~~~~~~~~~~~~~~~
| urid_ui_scaleFactor
/var/tmp/portage/media-libs/mlt-7.40.0/work/mlt-7.40.0/src/modules/jackrack/plugin_mgr.c:568:53: note: each undeclared identifier is reported only once for each function it appears in
```

`media-libs/lv2` needs to be fixed and autogenned

Reproduce media-libs/mlt-7.40.0 with the shown USE flags, then inspect the media-libs/lilv and media-libs/lv2 package definitions and autogeneration inputs. Done means the lilv include path is valid, LV2_UI__scaleFactor is available, and the mlt build completes without the reported CMake and compiler failures.

Written by the indexing model from the issue text.