guix gc: Error out when extra arguments are passed.

Fixes <http://bugs.gnu.org/21817>.
Reported by Petter Berntsen <petter@mykolab.ch>.

* guix/scripts/gc.scm (guix-gc)[assert-no-extra-arguments]: New
  procedure.
  Use it for actions 'collect-garbage', 'optimize', and 'verify'.
* tests/guix-gc.sh: Add tests.

guix package: '--search-paths' can report combined search paths.

Partly fixes <http://bugs.gnu.org/20255>.

* guix/scripts/package.scm (search-path-environment-variables): Change
  'profile' to 'profiles'; expect it to be a list.
  (display-search-paths): Likewise.
  (%default-options): Remove 'profile' entry.
  (%options) <--profile>: Keep previous values associated with 'profile'
  in RESULT.
  (guix-package)[process-actions, process-query]: Handle the possible
  lack of 'profile' pair in OPTS.

tests: Use the canonical current directory name.

* tests/guix-environment-container.sh (current_dir): New variable.  Use
  it when grepping "mounts".

tests: Skip 'program-file' test when shebang is too long.

* tests/gexp.scm ("program-file"): Skip when SHEBANG is too long.

import: pypi: Use "pypi-uri" instead of building the URL manually.

* guix/import/pypi.scm (make-pypi-sexp): Use "pypi-uri".
* tests/pypi.scm: Update the tests accordingly.

build: container: Add feature test predicates.

* gnu/build/linux-container.scm (user-namespace-supported?,
  unprivileged-user-namespace-supported?, setgroups-supported?): New
  procedures.
* tests/container.scm: Use predicates.
* tests/syscalls.scm: Likewise.

tests: Set 'SHELL' for 'guix environment'.

* tests/guix-environment.sh: Export 'SHELL'.

tests: Make sure the daemon dumps directory entries deterministically.

* tests/store.scm ("write-file & export-path yield the same result"):
  New test.

scripts: environment: Allow lists of packages in expressions.

* guix/scripts/environment.scm (options/resolve-packages): Match against
  lists of packages when evaluating expressions.
* tests/guix-environment.sh: Add test.
* doc/guix.texi ("invoking guix environment"): Add docs.

Merge branch 'master' into dbus-update

scripts: environment: Allow mixing regular and ad-hoc packages.

This patch changes the --ad-hoc flag to be positional.  That is, the
packages that appear before --ad-hoc are interpreted as packages whose
inputs should be in the environment; the packages that appear after are
interpreted as packages to be directly added to the environment.

* guix/scripts/environment.scm (tag-package-arg, compact): New
  procedures.
  (%options): Tweak the handlers for --load and --expression options.
  (options/resolve-packages): Preserve package mode tag.
  (parse-args): Tweak argument handler to use package tagging procedure.
  (guix-environment): Apply ad-hoc behavior on a per package basis.
* tests/guix-environment.sh: Add test.
* doc/guix.texi ("invoking guix environment"): Document new behavior of
  --ad-hoc.

tests: Print the mounts visible in the container.

* tests/guix-environment-container.sh: Print the content of
  $tmpdir/mounts.

scripts: build: Add --file option.

* guix/scripts/build.scm (show-help): Add help text for --file option.
  (%options): Add --file option.
  (options/resolve-packages): Handle 'file' options.
* tests/guix-build.sh: Add tests.
* doc/guix.texi ("invoking guix build"): Add doc.

substitute: Honor all the specified server URLs.

* guix/scripts/substitute.scm (lookup-narinfos/diverse): New procedure.
  (lookup-narinfo): Use it.
  (process-query): Change #:cache-url to #:cache-urls.
  [valid?]: Remove 'narinfo?' check, which is no longer necessary.
  Use 'lookup-narinfos/diverse' instead of 'lookup-narinfos'.
  (process-substitution): Change #:cache-url to #:cache-urls.
  (%cache-url): Rename to...
  (%cache-urls): ... this.  Turn into a list.
  (guix-substitute): Remove 'getaddrinfo' test with early exit.  Adjust
  calls to 'process-query' and 'process-substitution'.
* tests/substitute.scm: Change '%cache-url' to '%cache-urls'.

scripts: environment: Add --container option.

* guix/scripts/system.scm (specification->file-system-mapping): Move from
  here...
* guix/ui.scm (specification->file-system-mapping): ... to here.
* guix/scripts/enviroment.scm (show-help): Show help for new options.
  (%options): Add --container --network, --expose, and --share options.
  (%network-configuration-files): New variable.
  (launch-environment, launch-environment/container, requisites*,
  inputs->requisites): New procedures.
  (guix-environment): Spawn new process in a container when requested.
* doc/guix.texi (Invoking guix environment): Document it.
* tests/guix-environment-container.sh: New file.
* Makefile.am (SH_TESTS): Add it.

Merge branch 'master' into dbus-update

Add 'guix challenge'.

* guix/scripts/challenge.scm, tests/challenge.scm: New files.
* Makefile.am (MODULES): Add the former.
  (SCM_TESTS): Add the latter.
* doc.am (SUBCOMMANDS): Add 'challenge'.
* doc/guix.texi (Substitutes): Add xref to 'guix challenge'.
  (Invoking guix challenge): New node.
* doc/contributing.texi (Submitting Patches): Add note about using 'guix
  challenge'.
* po/guix/POTFILES.in: Add guix/scripts/challenge.scm.

guix archive: Add '--extract'.

* guix/scripts/archive.scm (show-help, %options): Add --extract.
  (guix-archive): Honor it.
* tests/guix-archive.sh: Test it.
* doc/guix.texi (Invoking guix archive): Document it.

Merge branch 'master' into dbus-update

services: Add 'dmd-service-back-edges'.

* gnu/services/dmd.scm (dmd-service-back-edges): New procedure.
* tests/services.scm ("dmd-service-back-edges"): New test.