* modules/past/packages/python27.scm (python2-scientific): New variable.

* modules/past/packages/python27.scm (python2-pyro): New variable.

* modules/past/packages/python27.scm (python2-numpy-1.8): New variable.

* modules/past/packages/python27.scm (python2-scipy): Update to 1.2.3.
[source]: Add snippet to remove cythonized files.
[arguments]: Add phase to cythonize files.

* modules/past/packages/python27.scm (python2-numpy): Update to 1.16.6.
[source]: Add snippet to remove cythonized file.
[arguments]: Add phase to generate cythonized file.

* modules/past/packages/python27.scm (python2-pandas): New variable.

* modules/past/packages/python27.scm (python2-beautifulsoup4): New
variable.

* modules/past/packages/python27.scm (python2-lxml): New variable.

* modules/past/packages/python27.scm (python2-openpyxl): New variable.

* modules/past/packages/python27.scm (python2-soupsieve): New variable.

* modules/past/packages/python27.scm (python2-pytest-mock): New variable.

* modules/past/packages/python27.scm (python2-mock): New variable.

* modules/past/packages/python27.scm (python2-singledispatch): New
variable.

* modules/past/packages/bioinformatics.scm (bamm): New variable.

* modules/past/packages/python27.scm (python2-package): Export it.

Later versions cannot be built with Python 2.

* modules/past/packages/python27.scm (python2-setuptools): Revert to
41.0.1.
[native-inputs]: Add unzip.

* modules/past/packages/python27.scm (python2-setuptools)[arguments]:
Add #:python argument.

* modules/past/packages/python27.scm (python2-nose): New variable.

* modules/past/packages/python27.scm (python2-cython)[arguments]: Set
 #:python argument.

* modules/past/packages/python27.scm (python2-setuptools): New variable.

* modules/past/packages/python27.scm (python2-scipy): New variable.

* modules/past/packages/python27.scm (python2-matplotlib): New variable.

* modules/past/packages/python27.scm (python2-dateutil): New variable.

* modules/past/packages/python27.scm (python2-pycairo): New variable.

* modules/past/packages/python27.scm (python2-subprocess32): New
variable.
* past/patches/python2-subprocess32-disable-input-test.patch: New file.

* modules/past/packages/python27.scm (python2-pygobject-2): New
variable.
* past/patches/python2-pygobject-2-deprecation.patch: New file.

* modules/past/packages/python27.scm (python2-functools32): New variable.

* modules/past/packages/python27.scm (python2-backports-functools-lru-cache):
New variable.

* modules/past/packages/python27.scm (python2-hypothesis): New variable.

* modules/past/packages/python27.scm (python2-pytest-cov): New variable.

* modules/past/packages/python27.scm (python2-enum34): New variable.

* modules/past/packages/python27.scm (python2-pillow)[arguments]: Use
python-2.

* modules/past/packages/python27.scm (python2-pillow): New variable.

* modules/past/packages/bioinformatics.scm: Use (past packages
python27).

Notably, this adds python2-numpy.

* modules/past/packages/python27.scm: New file.

* modules/past/packages/python.scm (python-3.8): New variable.
* modules/past/patches/python-3.8-arm-alignment.patch,
modules/past/patches/python-3.8-deterministic-build-info.patch,
modules/past/patches/python-3.8-fix-tests.patch,
modules/past/patches/python-3.8-fix-tests2.patch,
modules/past/patches/python-3.8-hurd-configure.patch,
modules/past/patches/python-3.8-search-paths.patch: New files.

This works around the lack of a fallback for the Subversion checkout of
GTNETS-SOURCE and also for fixed-output derivations in general.

* modules/past/packages/simgrid.scm (gtnets-zipball)
(gtnets-patch-tarball): Turn into origins, preserving sha256.

* modules/past/packages/maths.scm (lrslib-4.0)[arguments]: Add
'set-c-flags' phase.

* modules/past/packages/statistics.scm (r-minimal-2)[arguments]: Pass
CFLAGS and FFLAGS.

* modules/past/packages/simgrid.scm (simgrid-3.3)[arguments]: Pass
  #:configure-flags.