The Python interpreters are patched so they can build .pyc bytecode free
of certain indeterminism.
When building Python packages we currently set
```
compiling python files.
in nix store.
DETERMINISTIC_BUILD=1;
PYTHONHASHSEED = 0;
```
Instead if setting these environment variables in the function that
builds the package, this commit sets the variables instead in the Python
setup hook. That way, whenever Python is included in a derivation, these
variables are set.
See also the issue https://github.com/NixOS/nixpkgs/issues/25707.
This commit fixes several issues:
- as reported in https://github.com/NixOS/nixpkgs/issues/24924 it was
possible that the file _sysconfigdata.pyc was generated after the actual
build of the CPython interpreter. We forgot to regenerate that file
during the build. This is now fixed
- the expression of the 3.3 interpreter now also includes some of the
determinism patches even though the output isn't yet reproducible. The
reason for adding them is that this makes the expressions of the
different interpreters more similar.
- references to -dev packages are now also removed in the 3.6 package,
thereby reducing its closure size
From the manual:
> This attribute should be a number, with a higher value denoting a
lower priority. The default priority is 0.
Just passing -5 or -10 wasn't sufficient, so let's make it -100.
- Windows installers are indeterministic and we don't need them.
- since Python 3 ensurepip is installed by default. pip is indeteministic and we don't need it.
- rebuild bytecode to ensure its deterministic
A package set is constructed for a specific interpreter. Therefore, we add the
possibility to override the package set to the interpreter. This should make it
easier to override the interpreter and the package set at the same time.
In #19309 a separate output for tkinter was added.
Several dependencies of Python depend indirectly on Python. We have the
following two paths:
```
‘python-2.7.12’ - ‘tk-8.6.6’ - ‘libXft-2.3.2’ - ‘libXrender-0.9.10’ -
‘libX11-1.6.4’ - ‘libxcb-1.12’ - ‘libxslt-1.1.29’- ‘libxml2-2.9.4’ -
‘python-2.7.12’
‘python-2.7.12’ - ‘tk-8.6.6’ - ‘libXft-2.3.2’ - ‘fontconfig-2.12.1’ -
‘dejavu-fonts-2.37’ - ‘fontforge-20160404’ - ‘python-2.7.12’
```
Because only `tkinter` needs this, I added
```
pythonSmall = python.override {x11Support = false;};
```
to break the infinite recursion. We also still have the output
`tkinter`.
However, we might as well build without x11Support by default. Then we build with x11Support as well so we get the tkinter module and put that in a separate package.
