Augment '.dir-locals.el' with bug-reference-mode settings.

gnu: Add perl-zip.

* gnu/packages/zip.scm (perl-zip): New variable.

gnu: openssh: Update to 6.7p1.

* gnu/packages/ssh.scm (openssh): Update to 6.7p1.

Add copyright line to gnuzilla.scm.

* gnu/packages/gnuzilla.scm: Add copyright line for Mark H Weaver, which
  should have been added in 74c7af9 (gnu: icecat: Update to 31.1.1).

scripts: Add 'environment' command.

* guix/scripts/environment.scm: New file.
* Makefile.am (MODULES): Add it.
* doc/guix.texi ("Invoking guix environment"): New node.

build: Make sure tests/guix-package.sh doesn't leave anything behind it.

Fixes a regression introduced in commit 300868ba.

* tests/guix-package.sh: Move 'module_dir' definition to the top, and
  "rm -rf" it from the top-most 'trap'.  Remove second use of 'trap'.

doc: Add 'operating-system' reference.

* doc/guix.texi (Using the Configuration System): Add xref to
  "operating-system Reference".
  (operating-system Reference): New section.
  (Networking Services): Add xref to it.

doc: Use @deftp for 'build-machine'.

* doc/guix.texi (Daemon Offload Setup): Use @deftp for 'build-machine'.

gnu: icu4c: Correct error in the binaries' runpath

* gnu/packages/icu4c.scm (icu4c): Apply the RUNPATH to the binaries,
  instead of the libs

ui: Move 'show-manifest-transaction' from (guix profiles).

* guix/profiles.scm: Do not use (guix ui) module.
  (right-arrow, manifest-show-transaction): Move and rename to...
* guix/ui.scm (right-arrow, show-manifest-transaction): ... here.
* tests/profiles.scm ("manifest-show-transaction"): Move to...
* tests/ui.scm ("show-manifest-transaction"): ... here.
  (guile-1.8.8, guile-2.0.9): New variables.
* emacs/guix-main.scm (process-package-actions): Rename
  'manifest-show-transaction' to 'show-manifest-transaction'.
* guix/scripts/package.scm (guix-package): Likewise.

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

ui: Make sure we use the right domain for &message translation.

* guix/ui.scm (call-with-error-handling): Add %GETTEXT-DOMAIN as a
  second argument to 'gettext'.

Break module cycle involving (guix store) and (guix ui).

Before, there was a cycle along the lines of:

  (guix store) -> (guix nar) -> (guix ui) -> (guix store)

This caused problems, as discussed at:

  http://lists.gnu.org/archive/html/guix-devel/2014-10/msg00109.html

This patch removes cycles in the (guix ...) modules.

* guix/nar.scm (&nar-error, &nar-read-error, dump, write-contents,
  read-contents, %archive-version-1, write-file, restore-file): Move to...
* guix/serialization.scm: ... here.
* guix/store.scm: Remove dependency on (guix nar).
* guix/scripts/hash.scm, guix/scripts/offload.scm,
  guix/scripts/substitute-binary.scm, tests/nar.scm, tests/store.scm,
  tests/substitute-binary.scm: Adjust accordingly.

substitute-binary: Ignore $GUIX_BINARY_SUBSTITUTE_URL.

* guix/scripts/substitute-binary.scm (%cache-url): Ignore the
  'GUIX_BINARY_SUBSTITUTE_URL' environment variable.
* test-env.in: Invoke 'guix-daemon' with '--substitute-urls'.
* tests/substitute-binary.scm: Set '%cache-url' to the value of
  'GUIX_BINARY_SUBSTITUTE_URL'.

daemon: Add '--substitute-urls' option.

* nix/nix-daemon/guix-daemon.cc (GUIX_OPT_SUBSTITUTE_URLS): New macro.
  (GUIX_OPT_NO_BUILD_HOOK, GUIX_OPT_GC_KEEP_OUTPUTS,
  GUIX_OPT_GC_KEEP_DERIVATIONS): Renumber.
  (options): Add '--substitute-urls'.
  (parse_opt): Honor it.
  (main): Add 'settings.set' call for the default "substitute-urls"
  value.
* guix/scripts/substitute-binary.scm (daemon-options,
  find-daemon-option): New procedures.
  (%cache-url): Define based on the "substitute-urls" daemon option.
* doc/guix.texi (Invoking guix-daemon): Document '--substitute-urls'.
  (Substitutes): Mention it.

gnu: icecat: Update to 31.1.1.

* gnu/packages/gnuzilla.scm (icecat): Update to 31.1.1.  Add 'pango',
  'freetype', 'libxft' and 'pulseaudio' as inputs.  Set
  'out-of-source?' to #t.  Remove 'sanitise' phase.  Adapt customized
  'configure' phase to handle 'out-of-source?' build.  Add
  '--with-l10n-base' argument to configure.

monads: Add 'mbegin'.

* guix/monads.scm (mbegin): New macro.
* tests/monads.scm ("mbegin"): New test.
* doc/guix.texi (The Store Monad): Document it.

packages: Gracefully print packages whose 'location' is #f.

* guix/packages.scm (<package> printer): Check whether LOC is #f.
* tests/packages.scm ("printer with location", "printer without
  location"): New tests.

Add Federico to 'AUTHORS'.

doc: Document 'glib-or-gtk-build-system'.

* doc/guix.texi (Build System): Document 'glib-or-gtk-build-system'.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

gnu: cmake: Use our curl, zlib, expat, bzip2, and libarchive.

* gnu/packages/cmake.scm (cmake)[arguments]: Move sh-patching to new
  'patch-bin-sh phase.  New 'set-paths phase.
  [inputs]: Add curl, zlib, expat, bzip2, and libarchive.
  [description]: Fix space after end-of-sentence.