This should enable (manual) building of RPMs from python projects using
the `python setup.py bdist_rpm` command on systems where `rpmbuild` is
not located in `/usr/bin/`. (e.g. NixOS)
The discovery of the rpmbuild command was fixed upstream in Python 3.8,
so this commit backports the relevant patch to our currently supported
Python 3 versions.
Fixes: #85204
The upstream patch for distutils does not apply cleanly to Python
3.7.3's sources. (The patch applies cleanly to Python 3.7.2's sources,
but nixpkgs commit 0ddae82e6a upgraded
Python to 3.7.3.) Fix the patch to make python37 build on macOS.
Each time a new major/minor version of CPython was released, a new
expression would be written, typically copied from the previous release.
Often fixes are only made in the current/latest release. By merging the
expressions it's more likely that modifications end up in all versions,
as is likely intended.
This commit introduces one expression for Python 3, and another for 2.7.
These two may also be merged, but it will result in a lot of extra
conditionals making the expression harder to follow.
A common passthru is introduced for CPython and PyPy.
python 2.7: use common passthru
