Does anyone know why these errors are happening?

ERROR: ld.so: object 'libfakeroot.so' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored.
python36/src/Python-3.6.11/Modules/_decimal/_decimal.c:282:36: error: expected ';', ',' or ')' before 'UNUSED'
  282 | dec_traphandler(mpd_context_t *ctx UNUSED) /* GCOV_NOT_REACHED */
python36/src/Python-3.6.11/Modules/_decimal/_decimal.c:667:14: error: 'signaldict_len' undeclared here (not in a function); did you mean 'signaldict_repr'?
  667 |     (lenfunc)signaldict_len,          /* mp_length */
Failed to build these modules:
_decimal

pkgrel bumped, works again.

please make it support libffi.so.7

This needs a pkgrel bump since libffi was updated.

Because enabling optimizations adds a lot of build time – I for one would not upgrade my Python as regularly if every update took 40 minutes of heavy CPU use. Adding --enable-optimizations is, as you've seen, fairly doable on your own, but I think adding it by default would be a poor choice.

Why does this package not use --enable-optimizations?

I also face the same issue:

error: [Errno 2] No such file or directory: '/home/ubadmin/.cache/yay/python36/src/Python-3.6.10/Modules/_ctypes/libffi'
make: *** [Makefile:603: sharedmods] Error 1
==> ERROR: A failure occurred in build().
    Aborting...

I fixed it by installing the pkgconf package following this advice.

@walwe I had a similar issue to @ammonaur, but was able to resolve it:

Python36 installed correctly and the python3.6 symlink is properly under /usr/bin. Running "sudo python3.6 -m ensurepip" gives:

"Requirement already satisfied: setuptools in /usr/lib/python3.6/site-packages (40.0.0)

Requirement already satisfied: pip in /usr/lib/python3.6/site-packages (18.0)"

But pip3.6 cannot be found and python3.6 -m pip gives:

"/usr/bin/python3.6: No module named pip.main; 'pip' is a package and cannot be directly executed"

I looked at /usr/lib/python3.6/site-packages/pip and only see the _internal and _vendor folders. Compared to the corresponding py3.7 directory, it seems to be missing init.py and main.py which explains the error message above.

To fix: I deleted /usr/lib/python3.6/site-packages/pip and /usr/lib/python3.6/site-packages/pip-18.0.dist-info, then re-ran "sudo python3.6 -m ensurepip" which was successful and now pip3.6 works as well as python3.6 -m pip

I'm getting this error:

warning: building with the bundled copy of libffi is deprecated on this platform. It will not be distributed with Python 3.7 error: [Errno 2] No such file or directory: '/tmp/python36/src/Python-3.6.9/Modules/_ctypes/libffi' make: *** [Makefile:603: sharedmods] Error 1

I do have libffi installed. I wonder if that's normal the error is still occurring? Am I missing something? I have remove the rm _ctypes/libffi from the PKGBUILD in the mean time.

@ammonaur You can install pip3.6 using: sudo python3.6 -m ensurepip

After you can use "pip3.6 install" or "python3.6 -m pip install"