edit: Honor $VISUAL.

Suggested by Andreas Enge <andreas@enge.fr>.

* guix/scripts/edit.scm (%editor): Honor 'VISUAL' before 'EDITOR'.
  (show-help): Adjust accordingly.
* doc/guix.texi (Invoking guix edit): Likewise.

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.

install: Run GPM.

Suggested by Adam Pribyl <pribyl@lowlevel.cz>
at <https://lists.gnu.org/archive/html/guix-devel/2015-11/msg00133.html>.

* gnu/system/install.scm (installation-services): Add call to
  'gpm-service'.
* doc/guix.texi (System Installation): Mention GPM.

services: Add 'gpm-service'.

* gnu/services/base.scm (<gpm-configuration>): New record type.
  (gpm-dmd-service): New procedure.
  (gpm-service-type): New variable.
  (gpm-service): New procedure.
* doc/guix.texi (Base Services): Document it.

doc: Make the ifconfig command more visible.

Suggested by Adam Pribyl <pribyl@lowlevel.cz>.

* doc/guix.texi (System Installation): Move the 'ifconfig' command to an
  @example.

doc: Back up on the claim of encrypted root partitions.

Reported by 宋文武 <iyzsong@openmailbox.org>
at <https://lists.gnu.org/archive/html/guix-devel/2015-11/msg00096.html>.

* doc/guix.texi (System Installation): Comment out encrypted root
  partition commands.
* gnu/system/examples/desktop.tmpl (mapped-devices): Remove.
  (file-systems): Refer to the root by label.
* NEWS: Adjust.

doc: Fix typos.

* doc/guix.texi (Invoking guix refresh): Fix typos.

doc: Explain that 'guix publish' relies on the key pair.

* doc/guix.texi (Invoking guix publish): Mention 'guix archive
  --generate-key'.

import: pypi: add updater

* guix/import/pypi.scm (guix-package->pypi-name,
  latest-release): New procedures.
  (%pypi-updater): New variable.
* guix/scripts/refresh.scm (%updaters): Add %PYPI-UPDATER.
* doc/guix.texi (Invoking guix refresh): Mention PyPI

services: Add 'guix-publish-service'.

* gnu/services/base.scm (<guix-publish-configuration>): New record
  type.
  (guix-publish-dmd-service): New procedure.
  (%guix-publish-accounts, guix-publish-service-type): New variables.
  (guix-publish-service): New procedure.
* doc/guix.texi (Invoking guix publish): Add xref to
  'guix-publish-service' anchor.
  (Base Services): Document 'guix-publish-service'.

doc: Linux-libre 3.19 is needed for using containers.

* doc/guix.texi ("invoking guix environment", "invoking guix system"):
  3.10 is actually too old without backported patches, so change to 3.19.

doc: './pre-inst-env guix pull' won't upgrade local source tree.

* doc/contributing.texi (Running Guix Before It Is Installed): Clarify
  './pre-inst-env guix pull' won't upgrade local source tree.
* doc/guix.texi (Invoking guix pull): Mention ~/.config/guix/latest.

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

services: avahi: Add Avahi to the system profile.

* gnu/services/avahi.scm (avahi-service-type): Extend
  PROFILE-SERVICE-TYPE.
  (avahi-service): Adjust docstring.
* doc/guix.texi (Networking Services): Adjust accordingly.
* gnu/system/examples/desktop.tmpl (packages): Remove AVAHI.

services: wicd: Add Wicd to the system profile.

* gnu/services/networking.scm (wicd-service-type): Extend
  PROFILE-SERVICE-TYPE.
  (wicd-service): Mention it in docstring.
* doc/guix.texi (Networking Services): Update documentation
  accordingly.
* gnu/system/examples/desktop.tmpl (packages): Remove WICD.

services: Add 'profile-service-type'.

* gnu/services.scm (packages->profile-entry): New procedure.
  (profile-service-type): New variable.
* gnu/system.scm (operating-system-directory-base-entries): Remove
  the "profile" entry.
  (essential-services): Add a PROFILE-SERVICE-TYPE instance.
  (operating-system-profile): Rewrite in terms of 'fold-services'.
* doc/guix.texi (Service Reference): Add 'profile-service-type'.
* doc/images/service-graph.dot: Likewise.

services: Add 'system-service-type'.

* gnu/services.scm (system-derivation): New procedure.
  (system-service-type): New variable.
  (boot-script-entry): New procedure.
  (boot-service-type): Extend SYSTEM-SERVICE-TYPE.
  (etc-entry): New procedure.
  (etc-service-type): Extend SYSTEM-SERVICE-TYPE.
  (fold-services): Change default #:target-type to SYSTEM-SERVICE-TYPE.
* gnu/system.scm (operating-system-directory-base-entries): New procedure.
  (essential-services): Use it.  Add an instance of
  SYSTEM-SERVICE-TYPE.
  (operating-system-boot-script): Pass #:target-type to 'fold-services'.
  (operating-system-derivation): Rewrite in terms of 'fold-services'.
* gnu/system/linux-container.scm (system-container): Remove.
  (container-script): Use 'operating-system-derivation'.
* guix/scripts/system.scm (export-extension-graph): Replace
  BOOT-SERVICE-TYPE by SYSTEM-SERVICE-TYPE.
* doc/images/service-graph.dot: Add 'system' node and edges.
* doc/guix.texi (Service Composition): Mention SYSTEM-SERVICE-TYPE.
  (Service Reference): Document it.  Update 'fold-services'
  documentation.

doc: Fix typos.

* doc/guix.texi (Invoking guix environment): Fix typos.

doc: Fix typo.

* doc/guix.texi (Invoking guix container): Fix typo.

emacs: Enable 'guix-build-log-minor-mode' in shell buffers.

* emacs/guix-build-log.el (guix-build-log-minor-mode-activate): New variable.
  (guix-build-log-minor-mode-activate-maybe): New function.
* emacs/guix-init.el: Add it to 'shell-mode-hook'.
* doc/emacs.texi (Emacs Build Log): Mention it.

scripts: Add 'container' subcommand.

* guix/scripts/container.scm: New file.
* guix/scripts/container/exec.scm: New file.
* po/guix/POTFILES.in: Add them.
* Makefile.am (MODULES): Add them.
* doc/guix.texi (Invoking guix container): New section.