default cmake command produced: Could NOT find Threads (missing: Threads_FOUND)

[rmpowell77]

➜  build2 git:(main) ✗ cmake ..
...
CMake Error at /opt/homebrew/Cellar/cmake/3.20.5/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
  Could NOT find Threads (missing: Threads_FOUND)

Looks like it's similar to:
alicevision/geogram#2

assume built-in pthreads on MacOS

IF(APPLE)
set(CMAKE_THREAD_LIBS_INIT "-lpthread")
set(CMAKE_HAVE_THREADS_LIBRARY 1)
set(CMAKE_USE_WIN32_THREADS_INIT 0)
set(CMAKE_USE_PTHREADS_INIT 1)
set(THREADS_PREFER_PTHREAD_FLAG ON)
ENDIF()

[rmpowell77]

addressed in #357