Manually locate libffi for pyenv installation

[mrlasdt]

I am a beginner in pyenv. Every time I install a new Python version, I get the following output

>> from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
WARNING: The Python ctypes extension was not compiled. Missing the libffi lib?

Based on my search, the error is because the libffi-dev library is not installed, and a simple reinstallation should work. But, I don't have the root permission to install it.

$ dpkg -L libffi            
dpkg-query: package 'libffi' is not installed

Then, I tried to find a manual approach. In the built-in Python of the system, I see that the ctypes package can be imported

$ /usr/bin/python -c "import ctypes.util; print(ctypes.util.find_library('ffi'))"
libffi.so.7

I tried to find the libffi.so.7 file and get

$ find /usr/lib -name "libffi.so*"
/usr/lib/x86_64-linux-gnu/libffi.so.7.1.0
/usr/lib/x86_64-linux-gnu/libffi.so.7

Is there any possible way to proceed further?

[native-api]

Since -dev is headers and lib files, you can unpack the apt package manually and pass the path to CPython's Configure and/or CPPFLAGS/LDFLAGS.

https://askubuntu.com/questions/193695/installing-packages-into-local-directory also gives an option to install with Apt into a chroot jail -- which has the same effect but might be more convenient.