I'm using the tarball audacity-minsrc-3.0.2.tar.xz, CMake binary download cmake-3.20.2-linux-x86_64.tar.gz, on Debian 10.9.
CMake fails to find Jack giving this warning message:
I managed to find the file lib-src/portaudio-v19/cmake_support/FindJack.cmake and renamed it to Findjack.cmake (uppercase J to lowercase j). CMake seemed happy with this and gave no warning. Audacity built with no problems and I was able to use Jack.CMake Warning at cmake-proxies/portaudio-v19/CMakeLists.txt:91 (find_package):
By not providing "Findjack.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "jack", but
CMake did not find one.
Could not find a package configuration file provided by "jack" with any of
the following names:
Add the installation prefix of "jack" to CMAKE_PREFIX_PATH or set
"jack_DIR" to a directory containing one of the above files. If "jack"
provides a separate development package or SDK, be sure it has been
I don't know if this is a bug with CMake or a configuration issue with Audacity, however. I hope this is a valid bug report!