Jack support in latest snap installer version

[senjacob]

The Issue

Audacity Latest/Edge was not built with Jack audio support.
I am not sure if this fix should be in Audacity or here as additional patch for Ubuntu studio audacity package build support.

Compiling Audacity source is generating the following error.

-- ========== Configuring portaudio ==========
-- Using 'portaudio' local library
-- Found ALSA: /usr/lib/x86_64-linux-gnu/libasound.so (found version "1.2.4") 
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:

    jackConfig.cmake
    jack-config.cmake

  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
  installed.

The Fix/Workaround

I'm not much familiar with cmake, but this is how I got audacity 3.0.2 compiled with Jack support.

It seems compiling PortAudio is generating FindJack.cmake file. It is attached here, if it helps.
FindJack.cmake.zip

Audacity is checking for jackConfig.cmake, with lower-case j
I made small case change in the below line of audacity-minsrc-3.0.2/cmake-proxies/portaudio-v19/CMakeLists.txt
find_package( Jack )
Then I put the attached file in audacity-minsrc-3.0.2/lib-src/portaudio-v19/cmake_support/FindJack.cmake

This made Jack available in build output.

System Info

OS: Ubuntu 21.04 hirsute
Kernel: x86_64 Linux 5.11.0-16-lowlatency
Kernel and Jack2 was installed with Ubuntu studio installer.
PortAudio latest stable (pa_stable_v190700_20210406) was compiled and installed