This makes it consistent with the Nixpkgs fetchurl and makes it work
in chroots. We don't need verification because the hash of the result
is checked anyway.

The stack allocated for the builder was way too small (32 KB). This is
sufficient for normal derivations, because they just do some setup and
then exec() the actual builder. But for the fetchurl builtin
derivation it's not enough. Also, allocating the stack on the caller's
stack was fishy business.

Needed by Hydra.

This allows building a Raspberry Pi image on modern, faster boards.

CURLOPT_XFERINFOFUNCTION isn't widely supported yet.

http://hydra.nixos.org/build/26679495

This allows overriding the name component of the resulting Nix store
path, which is necessary if the base name of the URI contains
"illegal" characters.

This is in particular useful for fetchFromGitHub et al., ensuring that
the store path produced by nix-prefetch-url corresponds to what those
functions expect.

This allows nix-prefetch-url to prefetch the output of fetchzip and
its wrappers (like fetchFromGitHub). For example:

  $ nix-prefetch-url --unpack https://github.com/NixOS/patchelf/archive/0.8.tar.gz

or from a Nix expression:

  $ nix-prefetch-url -A nix-repl.src

In the latter case, --unpack can be omitted because nix-repl.src is a
fetchFromGitHub derivation and thus has "outputHashMode" set to
"recursive".

See https://github.com/NixOS/nixos-homepage/commit/d4a88df9d6114f609da889db62ef0a3bf6e4ef27

Update prerequisites-source.xml

For example,

  $ nix-prefetch-url -A hello.src

will prefetch the file specified by the fetchurl call in the attribute
‘hello.src’ from the Nix expression in the current directory. This
differs from ‘nix-build -A hello.src’ in that it doesn't verify the
hash.

You can also specify a path to the Nix expression:

  $ nix-prefetch-url ~/Dev/nixpkgs -A hello.src

List elements (typically used in ‘patches’ attributes) also work:

  $ nix-prefetch-url -A portmidi.patches.0

Also set CURLOPT_SSL_VERIFYHOST=0 when "verify-https-binary-caches" is false

This makes that option even more insecure, by also not checking the SSL host.

But without this parameter, one can still get SSL errors even when
"verify-https-binary-caches" is false, which is unexpected IMO.

release: fix #652 - PDF build after dblatex updates

... while not changing behavior when used with older nixpkgs.

nix-env --upgrade improvements

It was strange to show "upgrading" when the version was getting lower.
This is left on "upgrading" when the versions are the same,
as I can't see any better wording.

Until now, if one explicitly installed a low-priority version,
nix-env --upgrade would downgrade it by default and even with --leq.
Let's never accept an upgrade with version not matching the upgradeType.
Additionally, let's never decrease the priority of an installed package;
you can use --install to force that.

Also refactor to use variable bestVersion instead of bestName,
as only version was used from it.

The Perl WWW::Curl bindings are required to build Nix.

Fixes https://github.com/NixOS/nixpkgs/issues/9504.

Note that this means we may have a non-functional /bin/sh in the
chroot while rebuilding Bash or one of its dependencies. Ideally those
packages don't rely on /bin/sh though.

Fixes https://github.com/NixOS/nixos-homepage/issues/46.