bug#37989: python2-numpy v0.17.3 fails to build

[Josh Holland <josh@inv.alid.pw>]

Hi,

It seems that the update of python-numpy to 1.17.3 in
8e5fbd5dda93e137ff527cabe25989b28ab9e1c0 has broken the build of the
corresponding Python 2 package, both on my local machine and on the CI
server: http://ci.guix.gnu.org/build/1893145/details.

The log in Cuirass is incomplete, but the error in my build is the
following:

starting phase `build'
running "python setup.py" with command "build" and parameters ()
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "setup.py", line 31, in <module>
    raise RuntimeError("Python version >= 3.5 required.")
RuntimeError: Python version >= 3.5 required.
command "python" "-c" "import setuptools, tokenize;__file__='setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\\r\\n', '\\n');f.close();exec(compile(code, __file__, 'exec'))" "build" failed with status 1

Indeed, despite the assertion on
https://numpy.org/doc/1.17/user/building.html that Python 2.7 or 3.4 are
sufficient, the setup.py script explicitly checks that Python is at
least 3.5; see the upstream commit badf2901:

https://github.com/numpy/numpy/commit/badf2901ea040aa89dbb3c19e53c6b1b692cb489

Lots of packages including libreoffice transitively depend on
python2-numpy, so this needs some sort of resolution — perhaps simply
pinning python2-numpy to a previous version?  However, Python 2 will not
be maintained after the end of 2019, and I'm not sure if there is an
overall Guix-wide migration plan for python2-* packages.

--
Josh Holland