One of the motivations for this change is the following Discourse
discussion:

https://discourse.dhall-lang.org/t/offline-use-of-prelude/137

Many users have requested Dhall support for "offline" packages
that can be fetched/built/installed using ordinary package
management tools (like Nix) instead of using Dhall's HTTP import system.
I will continue to use the term "offline" to mean Dhall package
builds that do not use Dhall's language support for HTTP imports (and
instead use the package manager's support for HTTP requests, such
as `pkgs.fetchFromGitHub`)

The goal of this change is to document what is the idiomatic way to
implement "offline" Dhall builds by implementing Nixpkgs support
for such builds.  That way when other package management tools ask
me how to package Dhall with their tools I can refer them to how it
is done in Nixpkgs.

This change contains a fully "offline" build for the largest Dhall
package in existence, known as "dhall-packages" (not to be confused
with `dhallPackages`, which is our Nix attribute set containing
Dhall packages).

The trick to implementing offline builds in Dhall is to take
advantage of Dhall's support for semantic integrity checks.  If an
HTTP import is protected by an integrity check and a cached build
product matches the integrity check then the HTTP import is never
resolved and the expression is instead fetched from cache.

By "installing" dependencies in a pre-seeded and isolated cache
we can replace remote HTTP imports with dependencies that have
been built and supplied by Nix instead.

The offline nature of the builds are enforced by compiling the
Haskell interpreter with the `-f-with-http` flag, which disables
the interpreter's support for HTTP imports.  If a user forgets
to supply a necessary dependency as a Nix build product then the
build fails informing them that HTTP imports are disabled.

By default, built packages are "binary distributions", containing
just a cache product and a Dhall expression which can be used to
resolve the corresponding cache product.

Users can also optionally enable a "source distribution" of a package
which already includes the equivalent fully-evaluated Dhall code (for
convenience), but this is disabled by default to keep `/nix/store`
utilization as compact as possible.

There is no need to provide a separate `kubernetesVersion` argument
since the `file` argument works just fine

We don't compile blender with alembic. The linux build is able to detect
that, but this is not done for darwin. This explicitly disables alembic
to fix blender build on darwin.

... as requested by @Profpatsch

LibreOffice doesn't know where to look for hunspell dictionaries on
NixOS but we can use the DICPATH env var to point to them. Now
spellchecking with system dictionaries works.

Note that some of these dictionaries are built from LibreOffice repos -
this is preferable to building them as part of LO as other applications
can use them.

fixes #79805

 - Upgrade gildas to the latest version

 - Remove a patch that has been included upstream

 - Re-enable parallel building (fixed upstream)

https://github.com/GoogleContainerTools/skaffold/releases/tag/v1.4.0

lego already bundles the chain with the certificate,[1] so the current
code, designed for simp_le, was resulting in duplicate certificate
chains, manifesting as "Chain issues: Incorrect order, Extra certs" on
the Qualys SSL Server Test.

cert.pem stays around as a symlink for backwards compatibility.

[1] https://github.com/go-acme/lego/blob/5cdc0002e9abb2463fffc962dadc3479f72d7486/acme/api/certificate.go#L40-L44

Release notes: https://postgis.net/2020/02/20/postgis-3.0.1/

Fixes #80976

Changelog: https://github.com/Rigellute/spotify-tui/releases/tag/v0.15.0

spotify-tui: 0.14.0 -> 0.15.0

umoci: 0.4.4 -> 0.4.5

skaffold: 1.3.1 -> 1.4.0

* starting with rc2
* make `lldb` compilable again on Darwin
* separate out manpage creation for `lldb` into a new derivation
* minor tweaks to the patching of sources,
  some of which are backportable to earlier versions

postgresqlPackages.postgis: 3.0.0 -> 3.0.1

llvmPackages_10: init at rc2

Add Nixpkgs support for Dhall

Changelog: https://github.com/terraform-linters/tflint/releases/tag/v0.15.0

patroni: init at 1.6.4

gildas: 20200101_a -> 20200201_a

nixpkgs prefers absolute install names. Replace the manually specified
relative install name with the standard hook.

blender: 2.81a -> 2.82

Fast implementation of Dynamic Time Warping algorithm.

Dependency for qiskit-aqua.

Qiskit is a quantum information toolkit from IBM. This commit
follows the new Qiskit scheme of breaking from one large package into
smaller packages (terra, aer, etc), and then having a single
meta-package "qiskit" that comprises them.