How to force a python wheel to be platform specific when building it?

I am working on a python2 package in which the setup.py contains some custom install commands. These commands actually build some Rust code and output some .dylib files that are moved into the python package.

An important point is that the Rust code is outside the python package.

setuptools is supposed to detect automatically if the python package is pure python or platform specific (if it contains some C extensions for instance). In my case, when I run python setup.py bdist_wheel, the generated wheel is tagged as a pure python wheel: <package_name>-<version>-py2-none-any.whl. This is problematic because I need to run this code on different platforms, and thus I need to generated one wheel per platform.

Is there a way, when building a wheel, to force the build to be platform specific ?

Here's the code that I usually look at from uwsgi

The basic approach is:

setup.py

# ...

try:
    from wheel.bdist_wheel import bdist_wheel as _bdist_wheel
    class bdist_wheel(_bdist_wheel):
        def finalize_options(self):
            _bdist_wheel.finalize_options(self)
            self.root_is_pure = False
except ImportError:
    bdist_wheel = None

setup(
    # ...
    cmdclass={'bdist_wheel': bdist_wheel},
)

The root_is_pure bit tells the wheel machinery to build a non-purelib (pyX-none-any) wheel. You can also get fancier by saying there are binary platform-specific components but no cpython abi specific components.