Failing builds with pip in build environment

[mbargull]

Solution to issue cannot be found in the documentation.

• I checked the documentation.

Issue

Due to an issue with conda-libmamba-solver<->conda-build interaction, we had pip installed in the build environment for the numpy=1.26.2 update PR which caused the cross-compiled builds to fail with

Successfully built numpy-1.26.2-cp311-cp311-linux_aarch64.whl
+ pip install dist/numpy-1.26.2-cp311-cp311-linux_aarch64.whl
ERROR: numpy-1.26.2-cp311-cp311-linux_aarch64.whl is not a supported wheel on this platform.

@isuruf asked me to open an issue here too.

refs:

• numpy v1.26.2 numpy-feedstock#305 (comment) ff.
• Use "conda_build_tool": "mambabuild" as default again for now conda-smithy#1805
• add_pip_as_python_dependency (and others) ignored when run via conda-build conda/conda-libmamba-solver#393

Installed packages

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Environment info

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[mbargull]

From the discussion at conda-forge/numpy-feedstock#305 (comment) :
(The culprit there was calling pip executable directly.)

Would it be sensible to let it overwrite ${BUILD_PREFIX}/bin/pip too (if it exists)?

(Yes, I know about the bonkers "we explicitly give you a pip executable, but you should actually only ever use python -m pip" thing people say and I don't agree for obvious reasons.)