Add cffi 1.16.0

[auscompgeek]

Opening this draft so we have a thread to work on getting this to build.

From Dustin's comment:

You would probably need to download the opkg that NI created for libffi, unpack it, and somehow point cffi at it.

It looks like you can configure cffi's ffi library via pkg-config... https://github.com/python-cffi/cffi/blob/640e89fa97bd18bc4f69e714a4962284b83d5a76/setup.py#L20

[virtuald]

One of my TODOs is to get pkgconf-pypi integrated as part of 2025 changes, so this might be more doable in the future

[auscompgeek]

Is there some general guidance for how to get some opkgs from upstream into our sysroot?

[virtuald]

Not really?

An ipk is just an archive that you extract via ar x FILE.ipk (or use this python script), which yields control and data.tar.xx. The data tarfile just gets extracted into the root of the filesystem... so you could just extract it into the sysroot?

At one point I thought I had written a tool to transform a ipk to a wheel but I can't find it.