Some tests were made over Debian, Alpine and Fedora and the issue causing the FTBFS is present only on Debian. The Meson finds the libobs, but fails to build using it. Maybe it can be something related to #998853.
The upstream doesn't have a solution because he uses Alpine and the build is perfect there (this bug is unreproducible outside of Debian). My solution (or temporary solution): commonly, plugins for OBS are build with CMake, so I made a patch[1] to use it instead of Meson. This solution works fine and it is based in CMakeLists.txt files provided by Exeldro in several plugins, like obs-move-transition[2]. [1] https://salsa.debian.org/debian/obs-time-source/-/blob/debian/master/debian/patches/010_use-cmake.patch [2] https://salsa.debian.org/debian/obs-move-transition/-/blob/debian/master/CMakeLists.txt Eriberto