Set platform to any when running pip install

[davidfritzsche]

We want to vendor only Python-only distributions.

[pradyunsg]

Hmm... That looks about right. :)

I'm guessing you get a distribution not found error from pip, when this lookup fails?

[davidfritzsche]

@pradyunsg

If I try to install a package with only platform specific wheels using --platform any, then I get the following error message:

$ pip install --platform any --target /tmp/foo --no-deps protoc-wheel-0
ERROR: Could not find a version that satisfies the requirement protoc-wheel-0 (from versions: none)
ERROR: No matching distribution found for protoc-wheel-0