cffi shared library filenames are not prefixed by "lib" on linux and darwin

[doug-q]

Bug Description

For example see https://cffi.readthedocs.io/en/stable/embedding.html#id12.

Omitting this prefix makes it very challenging to link with these libraries whenever they have a SONAME, which will have the lib prefix. (When do they have a SONAME? it's not clear to me, except that it's clearly "sometimes").

See #1918

Your maturin version (maturin --version)

latest

Your Python version (python -V)

any

Your pip version (pip -V)

any

What bindings you're using

cffi

Does cargo build work?

• Yes, it works

If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)?

• Yes

Steps to Reproduce

1. configure a cffi maturin project
2. maturin develop
3. $ tree .

[messense]

Labeling this as a feature request to support cffi embedding instead of bug.