Python 3.7 configuration issue

[dieter]

Robin Becker <robin at reportlab.com> writes:

> On a Ubuntu trusty system I ran
> ./configure --prefix=/home/rptlab/PYTHON
> make && make install
> and get an error related to the ctypes module not being importable.
>
> I needed to do
>
> sudo apt-get install libffi-dev
> ./configure --prefix=/home/rptlab/PYTHON --with-system-ffi
> make && make install
>
> Something in setup.py seems to want ctypes irrespective of what I give
> to configure; I don't actually know what the alternative to
> --with-system-ffi does, but it didn't work for me.

"libffi" contains the so called "foreign function interface"
(an interface that allows code written in one language to call
code written in another language). Likely, "ctypes" depends
on it.

Since some time, "ctypes" is part of Python's standard library.
It is likely, that the Python test suite contains tests verifying
that it could be build successfully.

Your observations seem to indicate that "ctypes" contains its
own "foreign function interface" specification and that this
specification does not fit to the libraries available on your
system. The "with-system-ffi" likely tells the Python generation
process to use the system "foreign function interface" rather
than its own.