Channel branches are now provided in the nixpkgs repo.

Issue #71176.

This reverts commit 571fb74f

.

The dependency on gtk2 was removed.

Co-authored-by: Florian Klink <flokli@flokli.de>

This solves the dependency cycle in gcr alternatively so there won't be
two gnupg store paths in a standard NixOS system which has udisks2 enabled
by default.

NixOS users are expected to use the gpg-agent user service to pull in the
appropriate pinentry flavour or install it on their systemPackages and set
it in their local gnupg agent config instead.

Co-authored-by: Florian Klink <flokli@flokli.de>

Co-authored-by: Florian Klink <flokli@flokli.de>

Co-authored-by: Florian Klink <flokli@flokli.de>
Co-authored-by: worldofpeace <worldofpeace@protonmail.ch>

elm.elmPackages: Cleanup code

This is now done automatically.

This reverts commit d8218de5.
It makes no sense after the parent commit.

In our tests we have experienced failures of this test,
but it was otherwise not reproducible so far. A backported
upstream fix did not alleviate the issue either, so disabling
seems workable for now.

Now that Python 3.8 is released we will also build packages on Hydra.
As soon as the far majority of packages build, we can make Python 3.8
the default `python3`.

https://github.com/NixOS/nixpkgs/issues/71220

python37Packages.pathspec: 0.5.9 -> 0.6.0

- add comment specifying file is generated
- remove repetition of version number

pythonPackages.elementpath: 1.1.8 -> 1.3.0

cargo-deps: init at 1.1.1

coqPackages.coq-elpi: master → 1.1.0

GTK3 at version 3.24.11 has broken pkg-config files

ocamlPackages.psq: 0.1.0 → 0.2.0

zsh-history: init at unstable-2019-08-29

python37Packages.geopandas: 0.5.1 -> 0.6.0

assimp: 4.1.0 -> 5.0.0

prometheus: 2.12.0 -> 2.13.0

google-cloud-cpp: 0.11.0 -> 0.14.0