nextpnr fails to build with Python 3.9.0a2.

-- Found PythonInterp: /usr/bin/python3 (found suitable version "3.9", minimum required is "3.5") 
-- Found PythonLibs: /usr/lib64/libpython3.9.so (found suitable version "3.9.0a2", minimum required is "3.5") 
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE  
-- Found Boost: /usr/include (found version "1.69.0") found components: filesystem thread program_options iostreams chrono date_time atomic regex 
-- Found OpenGL: /usr/lib64/libOpenGL.so   
CMake Warning at /usr/share/cmake/Modules/FindBoost.cmake:2020 (message):
  No header defined for python-py3902; skipping header check (note:
  header-only libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:147 (find_package)
CMake Warning at /usr/share/cmake/Modules/FindBoost.cmake:2020 (message):
  No header defined for python-py390; skipping header check (note:
  header-only libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:154 (find_package)
CMake Warning at /usr/share/cmake/Modules/FindBoost.cmake:2020 (message):
  No header defined for python-py39; skipping header check (note: header-only
  libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:154 (find_package)
CMake Warning at /usr/share/cmake/Modules/FindBoost.cmake:2020 (message):
  No header defined for python-py3; skipping header check (note: header-only
  libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:154 (find_package)
CMake Warning at /usr/share/cmake/Modules/FindBoost.cmake:2020 (message):
  No header defined for python-3.9; skipping header check (note: header-only
  libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:175 (find_package)
CMake Error at CMakeLists.txt:182 (message):
  No version of Boost::Python 3.x could be found.
-- Configuring incomplete, errors occurred!


For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01195525-nextpnr/

For all our attempts to build nextpnr with Python 3.9, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/nextpnr/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.9:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/

Let us know here if you have any questions.

Python 3.9 will be included in Fedora 33. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.9.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.