* guix/scripts/environment.scm (show-environment-options-help): Document
--cwd.
(%options): Add cwd.
(launch-environment/container): Add cwd parameter.  Implement passing it to
the container.
(guix-environment*): Reject --cwd without --container.
* doc/guix.texi (Invoking guix shell): Document it.
* tests/guix-environment-container.sh: Add tests.
* tests/guix-shell.sh: Add tests.

Fixes: guix/guix# 7825
Change-Id: Iba4ff3d2058e92f504fbcbf688346357ce913213

Fixes a bug whereby ‘package->development-manifest’ would run with the
wrong system in mind, leading to errors like this:

  $ guix shell -s i586-gnu -D shepherd --no-grafts
  guix shell: error: package linux-libre-headers@5.15.49 does not support i586-gnu

* guix/scripts/environment.scm (options/resolve-packages): Define
‘system’ and pass it to ‘package->development-manifest’.’
* tests/guix-shell.sh: Test it.

Change-Id: I95c471c1918913ab80dec7d3ca64fe38583cce78

* tests/guix-shell.sh (fd_list): Use bash instead of $SHELL.  Some other
shells have trouble not opening too many fds.  Also, bash in an implicit input
of guix, so it should always be available.

Addresses <https://issues.guix.gnu.org/62406>.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&& false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... && false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

* guix/scripts/pack.scm (%options): Extract symlink parsing logic to...
(symlink-spec-option-parser): ... here.
(self-contained-tarball/builder): Add a comment mentioning why a relative file
name is used for the link target.
* guix/scripts/environment.scm (show-environment-options-help): Document new
--symlink option.
(%default-options): Add default value for symlinks.
(%options): Register new symlink option.
(launch-environment/container): Add #:symlinks argument and extend doc, and
create symlinks using evaluate-populate-directive.
(guix-environment*): Pass symlinks arguments to launch-environment/container.
* doc/guix.texi (Invoking guix shell): Document it.
* tests/guix-shell.sh: Add a --symlink (negative) test.
* tests/guix-environment-container.sh: Add tests.

Previously, 'guix shell' for example would leak the socket that's
connected to the daemon.

* guix/store.scm (open-unix-domain-socket, open-inet-socket): Pass
SOCK_CLOEXEC to 'socket'.
* tests/guix-shell.sh: Add test.

Previously user-facing commands would happily start building packages
even if they do not support that system.  With this change, all the
user-facing commands reject unsupported packages without going further.

* guix/profiles.scm (profile-derivation): Add #:allow-unsupported-packages?.
Define 'check-supported-packages' and honor #:allow-unsupported-packages?.
* tests/guix-pack.sh, tests/guix-package.sh, tests/guix-shell.sh: Ensure
that unsupported packages are rejected.
* tests/guix-system.sh: Pass "--system=armhf-linux" when attempting to
build gnu/system/examples/asus-c201.tmpl.

Fixes <https://issues.guix.gnu.org/52093>.
Reported by Konrad Hinsen <konrad.hinsen@fastmail.net>.

* guix/scripts/shell.scm (%options): In "--file" handler, add call to
'ensure-ad-hoc'.
* tests/guix-shell.sh: Add test.

This is a followup to 2a3cd4ee3557fbbdca42b5ec2f3ec4546c270203.

* tests/guix-shell.sh: Expect C_INCLUDE_PATH instead of CPATH.