Short version:

Try installing python 3.7.13 with pyenv: pyenv install 3.7.13, and if that does not work, try python 3.7.12 (pyenv install 3.7.12).

The pyenv release 2.2.3 addresses the compilation problems for 3.6.15/3.7.12 on M1 macs, specifically for ctypes.

Long version:

The underlying cause for the _ctypes error seems to be that libffi cannot be found during the compilation, and is therefore (silently) skipped during the Python installation.

There is a comprehensive overview for installing different versions using pyenv at this page, some specific versions require homebrew patches. Here is an overview of those patches. However, I would try installing them without the patches first, as the pyenv team has fixed various compilation problems since that post was written.

The general syntax for installing with a patch is: pyenv install --patch X.X.X <<(curl -sSL link_to_patch) where X.X.X is the version you want to install.

Another solution is to use an x86 version of homebrew.

Officially, Python 3.7 and lower are not supported on Apple Silicon.

The following script works on my MacBook Pro (M1, 2020), MacOS: Big Sur 11.5.2. I hope this is helpful.

# Install x86 brew
arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
alias ibrew=/usr/local/bin/brew

# Install Python 3.7
arch -x86_64 ibrew install python@3.7

# Add `python` executable (symlink to `python3`)
ln -s python3 "$(ibrew --prefix python@3.7)"/bin/python

# Symlink x86 Python 3.7 into pyenv
ln -s "$(ibrew --prefix python@3.7)" .pyenv/versions/3.7.10

# Check
pyenv local 3.7.10
python -V
# Python 3.7.10
python -c 'import _ctypes'. # works!

reference: https://github.com/pyenv/pyenv/issues/1768#issuecomment-871602950

Install the libffi development package:

sudo apt-get install libffi-dev

and try again.

Required

Install foreign function interface headers

sudo apt install libffi-dev

Reinstall Python

Substitute desired python version

Ubuntu

sudo add-apt-repository ppa:deadsnakes/ppa -y && sudo apt install --reinstall python3.9-distutils

MacOS

Use brew install python3.9 or port install python3.9 (I recommend port)

Windows

Use Microsoft Store

Specify project python version

Poetry

poetry env use 3.9

Virtual envs

virtualenv -p python3.9 myproject

etc...