Can't find AudacityFunctions when building

Programming and Development Compiling Audacity
1

I downloaded the latest source, made a build directory, switched into it, ran cmake -G “Unix Makefiles” ../audacity get:

CMake Error at CMakeLists.txt:179 (include):
  include could not find requested file:

    AudacityFunctions


CMake Error at CMakeLists.txt:181 (set_from_env):
  Unknown CMake command "set_from_env".


-- Configuring incomplete, errors occurred!

Linux, Kernel 6.18.2, Slackware