Not sure how this ever worked but tar was trying to archive /proc and /sys, which failed to work.
Since this is never useful for containers to do, we exclude this now in the proot case.
Also fakeroot is not needed when proot is used as it provideds the same feature.
We now cleanly seperate those cases as both are kind of hacks and it's more likely
that the combination will just trigger new bugs.
Some programs (e.g. nvfetcher) parse the output of nix-prefetch-git as
JSON. However, there is a pushd/popd command in nix-prefetch-git that
outputs the directory name, breaking the structure of the result JSON.
We suppressed it with `>/dev/null`.
Passingly fixes a mixuse of tab and spaces.
This script needs to support being run both as part of a `fetchgit`
derivation and as a standalone, command-line tool.
The use of `$NIX_BUILD_TOP` only works when used in `fetchgit` but not when
invoked as a standalone tool. Instead we try to respect `$NETRC` so that
the command-line invocation behaves more like standard tools and the
`fetchgit` derivation can explicitly set `$NETRC` when `netrcPhase` is used
to avoid all ambiguity.
We need this stuff to be available in lib so make-derivation.nix can
access it to construct the Meson cross file.
This has a couple of other advantages:
- It makes Rust less special. Now figuring out what Rust calls a
platform is the same as figuring out what Linux or QEMU call it.
- We can unify the schema used to define Rust targets, and the schema
used to access those values later. Just like you can set "config"
or "system" in a platform definition, and then access those same
keys on the elaborated platform, you can now set "rustcTarget" in
your crossSystem, and then access "stdenv.hostPlatform.rustcTarget"
in your code.
"rustcTarget", "rustcTargetSpec", "cargoShortTarget", and
"cargoEnvVarTarget" have the "rustc" and "cargo" prefixes because
these are not exposed to code by the compiler, and are not
standardized. The arch/os/etc. variables are all named to match the
forms in the Rust target spec JSON.
The new rust.target-family only takes a list, since we don't need to
worry about backwards compatibility when that name is used.
The old APIs are all still functional with no warning for now, so that
it's possible for external code to use a single API on both 23.05 and
23.11. We can introduce the warnings once 23.05 is EOL, and make them
hard errors when 23.11 is EOL.
Arguably, this is a bug in Nix's structuredAttrs: without
structuredAttrs, exportReferencesGraph with an empty path set would
still result in information being provided. With structuredAttrs, no
info is provided for an empty path set.
Nevertheless, we need to be able to build even if Nix has the bug, so
work around it by checking for an empty path set and handling it
explicitly.
