This hopefully makes patchShebangs respect cross compilation. It
introduces the concept of the HOST_PATH. Nothing is ever executed on
it but instead used as a way to get the proper path using ‘command
-v’. Needs more testing.

/cc @Ericson2314 @dtzWill

Fixes #33956
Fixes #21138

The ‘mesa-darwin’ stuff was very out of date (2012). This moves darwin
to use the newer mesa. Stuff seems to build okay. Needs more testing
on other stuff though (libraries work). No drivers build but that is
how it should work on macOS.

/cc @cstrahan @Anton-Latukha

Show the filename on unsupported shebang error.
Simplifies debugging packages with large set of scripts.

Turns out the filename is important. It should be `cblas`, not
`openblas-cblas`.

openblas: fix pkg-config alias name

Hydra: ?compare=1477053

It was reported that the 2nd solution wasn't working as expected because
it was ran in the wrong phase.

This commit creates a new phase, in between the installCheckPhase and distPhase.

https://www.sudo.ws/stable.html

(may need to scroll to the 1.8.25 notes
afternewer versions are released)

Works similarly to `enableParallelBuilding`, but is set by default when
`enableParallelBuilding` is set. In my experience most packages that build
fine in parallel also check fine in parallel.

vala: 0.34.17 -> 0.34.18, 0.36.13 -> 0.36.15, 0.38.9 -> 0.38.10, 0.40.6 -> 0.40.9

stdenv: implement enableParallelChecking option

patch-shebangs: respect cross compilation

Semi-automatic update generated by
https://github.com/ryantm/nixpkgs-update tools. This update was made
based on information from
libdrm

54282b9 tread carefuly to avoid a mass
rebuild. This embraces the mass rebuild to clean things up.

mesa: remove darwin-specific derivations

merge: master to staging

coreutils: try 8.30 again, fix bootstrap tools expression motivating revert before

numpy, scipy: Fix some nativeBuildInputs

This causes problems for packages built using a bootstrap stdenv,
resulting in references to /bin/sh or even bootstrap-tools. The darwin
stdenv is much stricter about what requisites/references are allowed but
using /bin/sh on linux is also undesirable.

eg. https://hydra.nixos.org/build/81754896

    $ nix-build -A xz
    $ head -n1 result-bin/bin/xzdiff
    #!/nix/store/yvc7kmw98kq547bnqn1afgyxm8mxdwhp-bootstrap-tools/bin/sh

This reverts commit f069423.

As in the other cases, I didn't care about passing the dependency
if unused...

It's a bit weird that noone's noticed,
but I guess it's because of a merge or rebase.