I am willing to maintain jack-audio-connection-kit and update it to version 1.9.21.
Fixes are following:

• Add shell mode to jack_control (executes commands from stdin until EOF)
• The waf autooption --example-tools introduced in 1.9.20 is now off by default, To get the previous behavior back pass --example-tools during build. This flag (and the related tools and their code) are going to be removed in the next release.
• Fix alignas() on non-packed architectures
• Fix build of jack-example-tools man pages (1.9.20 regression)
• Fix compatibility with macOS 12
• Fix missing symbols from jack client library (error and info callback pointers)
• Fix potential memory corruption in midi_latency_test tool
• Fix JackWeakAPI on Windows
• Use predefined variables in pkg-config file (required for mingw)