Use the attr set instead of a string

patchelf: fix license

The darwin build started to fail because of protobuf c++11 related
errors https://hydra.nixos.org/build/82082958.

mosh: fix clang build

This reverts commit f309440.

Breaks manual build:

https://nix-cache.s3.amazonaws.com/log/wnjcy6n5f871bpyy9nd06smiz1ggv99c-nixos-manual-combined.drv

environment.sessionVariables cannot refer to the values of env vars,
and as a result this has caused problems in a variety of scenarios.

One use for these is that they're injected into /etc/profile,
elewhere these are used to populate an 'envfile' for pam
(`pam 5 pam_env.conf`) which mentions use of HOME being
potentially problematic.

Anyway if the goal is to make things easier for users,
simply do the NIX_PATH modification as extraInit.

This fixes the annoying problems generated by the current approach
(#40165 and others) while hopefully serving the original goal.

One way to check if things are borked is to try:

$ sudo env | grep NIX_PATH

Which (before this change) prints NIX_PATH variable with
an unexpanded $HOME in the value.

-------

This does mean the following won't contain user channels for 'will':
$ sudo -u will nix-instantiate --eval -E builtins.nixPath

However AFAICT currently they won't be present either,
due to unescaped $HOME.  Unsure if similar situation for other users
of sessionVariables (not sudo) work with current situation
(if they exist they will regress after this change AFAIK).

Per reviewer comment (thanks!).

I fixed the problem.

This reverts commit 74df71b.

zig: 0.2.0 -> 0.3.0

libreoffice-fresh: 6.1.1.2 -> 6.1.2.1