Supply the extra pip args in the resolver.

[matteius]

Extra pip args were never passed to the resolver. The way this PR does it, allows it to work for both the default resolver in sub-process and resolver in parent process options.

The issue

Fixes #6001

The fix

Example of using this branch:

$ pipenv install --verbose --extra-pip-args "--platform=win_amd64 --target C:\\c\\Users\\matte\\.virtualenvs\\issue-6001-WKuyds7q\\Lib\\site-packages\\"  tensorflow
Installing tensorflow...
Resolving tensorflow...
Installation Succeeded
Installing dependencies from Pipfile.lock (3b7552)...

[...]

Successfully installed absl-py-2.0.0 astunparse-1.6.3 cachetools-5.3.2 flatbuffers-23.5.26 gast-0.5.4 google-auth-2.23.4 google-auth-oauthlib-1.0.0 google-pasta-0.2.0 grpcio-1.59.2 h5py-3.10.0 keras-2.14.0
libclang-16.0.6 markdown-3.5.1 markupsafe-2.1.3 ml-dtypes-0.2.0 numpy-1.26.1 oauthlib-3.2.2 opt-einsum-3.3.0 packaging-23.2 protobuf-4.25.0 pyasn1-0.5.0 pyasn1-modules-0.3.0 requests-oauthlib-1.3.1 rsa-4.9
six-1.16.0 tensorboard-2.14.1 tensorboard-data-server-0.7.2 tensorflow-2.14.0 tensorflow-estimator-2.14.0 tensorflow-intel-2.14.0 tensorflow-io-gcs-filesystem-0.31.0 termcolor-2.3.0 typing-extensions-4.8.0
werkzeug-3.0.1 wheel-0.41.3 wrapt-1.14.1

Install Phase: Editable Requirements
[...]

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.

[oz123]

How is extra_pip_args passed here? Is it a dict or a string?

Can you add a test for that? Or at least a comment?

[matteius]

I believe it is a string, I'll revisit soon.