Provisional pyproject RPM macros: Dynamic BuildRequires for Python packages

[Miro Hrončok]

Hello fellow Python packagers. This is an announcement about a new set of RPM 
macros you can use to build PEP 517/518 enabled packages, that is Python 
packages that have the pyproject.toml file.

   https://www.python.org/dev/peps/pep-0517/
   https://www.python.org/dev/peps/pep-0518/
   https://snarky.ca/clarifying-pep-518/

The set of macros is designed for modern packaging with dynamic buildrequires in 
mind.
The macros are in the pyproject-rpm-macros package and you can use them like this:

     BuildRequires:  pyproject-rpm-macros

     %prep
     ...

     %generate_buildrequires
     %pyproject_buildrequires -t

     %build
     %pyproject_wheel

     %install
     %pyproject_install

     %check
     %tox

See the full documentation of the macros:
  https://src.fedoraproject.org/rpms/pyproject-rpm-macros/blob/master/f/REA...

See example spec files:
  https://src.fedoraproject.org/rpms/pyproject-rpm-macros/blob/master/f/tests

(These use setuptools (setup.py), flit and poetry for build backends, but you 
cannot tell that from the specfiles - BuildRequires are generated dynamically 
from upstream metadata.)

The macros are **provisional**, i.e. their API may be changed upon feedback 
received from you.
We are not (yet) interested in a general "update all the Python packages" hunt,

but rather in early adopters.

If you have questions, ask here. We'll gladly extend the docs if something is 
not clear.
If you find bugs, report them in bugzilla or here. Likewise for RFEs.

Happy hacking,
Python Maintenance