services: Introduce extensible services.

This patch rewrites GuixSD services to make them extensible.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/dbus.scm.
* gnu/services.scm (<service>): Replace with new record type.
  (<service-extension>, <service-type>): New record types.
  (write-service-type, compute-boot-script, second-argument): New
  procedures.
  (%boot-service, boot-service-type): New variables.
  (file-union, directory-union, modprobe-wrapper,
  activation-service->script, activation-script,
  gexps->activation-gexp): New procedures.
  (activation-service-type, %activation-service): New variables.
  (etc-directory, files->etc-directory, etc-service): New procedures.
  (etc-service-type, setuid-program-service, firmware-service-type): New
  variables.
  (firmware->activation-gexp): New procedure.
  (&service-error, &missing-target-service-error,
  &ambiguous-target-service-error): New condition types.
  (service-back-edges, fold-services): New procedures.
* gnu/services/avahi.scm (<avahi-configuration>): New record type.
  (configuration-file): Replace keyword parameters with a single
  'config' parameter.
  (%avahi-accounts, %avahi-activation, avahi-service-type): New
  variables.
  (avahi-dmd-service): New procedure.
  (avahi-service): Rewrite using 'service' and 'avahi-configuration'.
* gnu/services/base.scm (%root-file-system-dmd-service,
  root-file-system-service-type): New variables.
  (root-file-system-service): Use them.
  (file-system->dmd-service-name): New procedure.
  (file-system-service-type): New variable.
  (file-system-service): Use it.  Replace keyword parameters with a
  single 'file-system' object.
  (user-unmount-service-type): New variable.
  (user-unmount-service): Use it.
  (user-processes-service-type): New variable.
  (user-processes-service): Use it.
  (host-name-service-type): New variable.
  (host-name-service): Use it.
  (console-keymap-service-type): New variable.
  (console-keymap-service): Use it.
  (console-font-service-type): New variable.
  (console-font-service): Use it.
  (mingetty-pam-service, mingetty-dmd-service): New procedures.
  (mingetty-service-type): New variable.
  (mingetty-service): Use it.
  (nscd-dmd-service): New procedure.
  (nscd-activation, nscd-service-type): New variables.
  (nscd-service): Use the latter.
  (syslog-service-type): New variable.
  (syslog-service): Use it.
  (<guix-configuration>): New record type.
  (%default-guix-configuration): New variable.
  (guix-dmd-service, guix-accounts, guix-activation): New procedures.
  (guix-service-type): New variable.
  (guix-service): Replace list of keyword parameters with a single
  'config' parameter.  Rewrite using 'service'.
  (<udev-configuration>): New record type.
  (udev-dmd-service): New procedure.
  (udev-service-type): New variable.
  (udev-service): Use it.
  (device-mapping-service-type): New variable.
  (device-mapping-service): Use it.
  (swap-service-type): New variable.
  (swap-service): Use it.
* gnu/services/databases.scm (<postgresql-configuration>): New record
  type.
  (%postgresql-accounts, postgresql-activation): New variables.
  (postgresql-dmd-service): New procedure.
  (postgresql-service): Rewrite using 'service' and
  'postgresql-configuration'.
* gnu/services/dbus.scm: New file.
* gnu/services/desktop.scm (dbus-configuration-directory, dbus-service):
  Remove.
  (wrapped-dbus-service): New procedure.
  (<upower-configuration>): New record type.
  (upower-configuration-file): Replace keyword parameters with single
  <upower-configuration> parameter.
  (%upower-accounts, %upower-activation): New variables.
  (upower-dbus-service, upower-dmd-service): New procedures.
  (upower-service-type): New variable.
  (upower-service): Rewrite using 'service' and 'upower-configuration'.
  (%colord-activation, %colord-accounts): New variables.
  (colord-dmd-service): New procedure.
  (colord-service-type): New variable.
  (colord-service): Rewrite using 'service'.
  (<geoclue-configuration>): New record type.
  (geoclue-configuration-file): Replace keyword parameters with a single
  'config' parameter.
  (geoclue-dbus-service, geoclue-dmd-service): New procedures.
  (%geoclue-accounts, geoclue-service-type): New variables.
  (geoclue-service): Rewrite using 'service' and
  'geoclue-configuration'.
  (%polkit-accounts, %polkit-pam-services, polkit-service-type): New
  variables.
  (polkit-dmd-service): New procedure.
  (polkit-service): Rewrite using 'service'.
  (<elogind-configuration>)[elogind]: New field.
  (elogind-dmd-service): New procedure.
  (elogind-service-type): New variable.
  (elogind-service): Rewrite using 'service'.
  (%desktop-services): Remove argument to 'dbus-service'.  Remove 'map'
  over %BASE-SERVICES.
* gnu/services/dmd.scm (dmd-boot-gexp): New procedure.
  (dmd-root-service-type, %dmd-root-service): New variables.
  (dmd-service-type): New macro.
  (<dmd-service>): New record type.
* gnu/services/lirc.scm (<lirc-configuration>): New record type.
  (%lirc-activation): New variable.
  (lirc-dmd-service): New procedure.
  (lirc-service-type): New variable.
  (lirc-service): Rewrite using 'service' and 'lirc-configuration'.
* gnu/services/networking.scm (<static-networking>): New record type.
  (static-networking-service-type): New variable.
  (static-networking-service): Rewrite using 'service' and
  'static-networking'.
  (dhcp-client-service-type): New variable.
  (dhcp-client-service): Rewrite using 'service'.
  (<ntp-configuration>): New record type.
  (ntp-dmd-service): New procedure.
  (ntp-service-type): New variable.
  (ntp-service): New procedure.
  (%tor-accounts, tor-service-type): New variable.
  (tor-dmd-service): New procedure.
  (tor-service): Rewrite using 'service'.
  (<bitlbee-configuration>): New record type.
  (bitlbee-dmd-service): New procedure.
  (%bitlbee-accounts, %bitlbee-activation, bitlbee-service-type): New
  variables.
  (bitlbee-service): Rewrite using 'service'.
  (%wicd-activation): New variable.
  (wicd-dmd-service): New procedure.
  (wicd-service-type): New variable.
  (wicd-service): Rewrite using 'service'.
* gnu/services/ssh.scm (<lsh-configuration>): New record type.
  (activation): Rename to...
  (lsh-initialization): ... this.
  (lsh-activation, lsh-dmd-service, lsh-pam-services): New procedures.
  (lsh-service-type): New variable.
  (lsh-service): Rewrite using 'service' and 'lsh-configuration'.
* gnu/services/web.scm (<nginx-configuration>): New record type.
  (%nginx-accounts): New variable.
  (nginx-activation, nginx-dmd-service): New procedures.
  (nginx-service-type): New variable.
  (nginx-service): Rewrite using 'service' and 'nginx-configuration'.
* gnu/services/xorg.scm (<slim-configuration>): New record type.
  (slim-pam-service, slim-dmd-service): New procedures.
  (slim-service-type): New variable.
  (slim-service): Rewrite using 'service' and 'slim-configuration'.
* gnu/system.scm (file-union): Remove.
  (other-file-system-services): Adjust to new 'file-system-service'
  signature.
  (essential-services): Add #:container? parameter.  Add
  %DMD-ROOT-SERVICE, %ACTIVATION-SERVICE, and calls to
  'pam-root-service', 'account-service', 'operating-system-etc-service',
  and a SETUID-PROGRAM-SERVICE instance.
  (operating-system-services): Pass #:container? to 'essential-services.
  (etc-directory): Remove.
  (operating-system-etc-service): New procedure.  Rewrite as a call to
  'etc-service'.
  (operating-system-accounts): Change to not return accounts required by
  services.
  (operating-system-etc-directory): Rewrite as a call to 'fold-services'
  and 'etc-directory'.
  (user-group->gexp, user-account->gexp, modprobe-wrapper): Remove.
  (operating-system-activation-script): Rewrite as a call to
  'fold-services' and 'activation-service->script'.
  (operating-system-boot-script): Likewise.
  (operating-system-derivation): Add call to 'lower-object'.
  (emacs-site-file, emacs-site-directory, shells-file): Change to use
  'computed-file' and 'scheme-file' instead of the monadic procedures.
* gnu/system/install.scm (cow-store-service-type): New variable.
  (cow-store-service): Rewrite using 'service'.
  (/etc/configuration-files): New procedure.
  (configuration-template-service-type,
  %configuration-template-service): New variables.
  (configuration-template-service): Remove.
  (installation-services): Adjust accordingly.  Adjust argument to
  'guix-service'.
* gnu/system/linux.scm (/etc-entry, pam-root-service): New procedures.
  (pam-root-service-type): New variable.
* gnu/system/shadow.scm (user-group->gexp, user-account->gexp,
  account-activation, etc-skel, account-service): New procedures.
  (account-service-type): New variable.
* tests/services.scm: New file.
* doc/guix.texi (Base Services, Desktop Services): Adjust accordingly.
  (Defining Services): Rewrite.
* doc/images/service-graph.dot: New file.
* doc.am (DOT_FILES): Add it.
* po/guix/POTFILES.in: Add gnu/services.scm.

Merge branch 'master' into core-updates

Add (guix scripts).

* guix/ui.scm: Add missing copyright lines.
  (args-fold*, environment-build-options, %default-argument-handler,
  parse-command-line): Move to ...
* guix/scripts.scm: ...here.  New file.
* guix/scripts/archive.scm: Use it.
* guix/scripts/build.scm: Likewise.
* guix/scripts/download.scm: Likewise.
* guix/scripts/edit.scm: Likewise.
* guix/scripts/environment.scm: Likewise.
* guix/scripts/gc.scm: Likewise.
* guix/scripts/graph.scm: Likewise.
* guix/scripts/hash.scm: Likewise.
* guix/scripts/import/cpan.scm: Likewise.
* guix/scripts/import/cran.scm: Likewise.
* guix/scripts/import/elpa.scm: Likewise.
* guix/scripts/import/gem.scm: Likewise.
* guix/scripts/import/gnu.scm: Likewise.
* guix/scripts/import/hackage.scm: Likewise.
* guix/scripts/import/nix.scm: Likewise.
* guix/scripts/import/pypi.scm: Likewise.
* guix/scripts/lint.scm: Likewise.
* guix/scripts/package.scm: Likewise.
* guix/scripts/publish.scm: Likewise.
* guix/scripts/pull.scm: Likewise.
* guix/scripts/refresh.scm: Likewise.
* guix/scripts/size.scm: Likewise.
* guix/scripts/system.scm: Likewise.
* tests/ui.scm (with-environment-variable, "parse-command-line",
  "parse-command-line and --no options"): Move to ...
* tests/scripts.scm: ...here.  New file.
* Makefile.am (MODULES): Add guix/scripts.scm.
  (SCM_TESTS): Add tests/scripts.scm.
* po/guix/POTFILES.in: Add guix/scripts.scm.

Merge branch 'master' into core-updates

import: gem: Fix minor bug and add unit test.

* guix/import/gem.scm (make-gem-sexp): Properly handle an empty list of
  licenses.  When rendering a list of licenses, cons 'list onto the front of
  the expression.
* tests/gem.scm: New file.
* Makefile.am (SCM_TESTS): Add it.

build: Add R build system.

* guix/build-system/r.scm: New file.
* guix/build/r-build-system: New file.
* Makefile.am (MODULES): Add new files.
* doc/guix.texi (Build Systems): Document r-build-system.

import: Add 'cran' importer.

* guix/import/cran.scm: New file.
* guix/scripts/import.scm: Add "cran" to 'importers'.
* guix/scripts/import/cran.scm: New file.
* tests/cran.scm: New file.
* Makefile.am (MODULES): Add 'guix/import/cran.scm' and
  'guix/scripts/import/cran.scm'.
  (SCM_TESTS): Add 'tests/cran.scm'.
* doc/guix.texi (Invoking guix import): Document it.
* po/guix/POTFILES.in: Add 'guix/scripts/import/cran.scm'.

import: Add Ruby gem importer.

* gnu/scripts/import.scm (importers): Add "gem".
* gnu/import/gem.scm: New file.
* gnu/scripts/import/gem.scm: New file.
* Makefile.am (MODULES): Add them.
* guix.texi ("invoking guix import"): Document it.

Add 'guix graph'.

* guix/scripts/graph.scm, tests/graph.scm, tests/guix-graph.sh,
  doc/images/coreutils-bag-graph.dot, doc/images/coreutils-graph.dot: New
  files.
* Makefile.am (MODULES): Add guix/scripts/graph.scm.
  (SH_TESTS): Add tests/guix-graph.sh.
  (SCM_TESTS): Add tests/graph.scm.
* doc.am (DOT_FILES, DOT_VECTOR_GRAPHICS): New variables.
  (EXTRA_DIST): Use them.
  (dist_infoimage_DATA): Use $(DOT_FILES).
  (pdf-local, info-local, ps-local): Likewise.
* doc/guix.texi (Packages with Multiple Outputs): Add cross-reference to 'guix
  graph'.
  (Invoking guix gc): Likewise.
  (Invoking guix graph): New section.

build: Do not build (guix build syscalls) if 'mount' is missing from libc.

This disables compilation of this module on GNU/Hurd.
Reported by Manolis Ragkousis <manolis837@gmail.com>.

* m4/guix.m4 (GUIX_CHECK_LIBC_MOUNT): New variable.
* configure.ac: Use it.  Define 'BUILD_SYSCALLS_MODULE' conditional.
* Makefile.am (MODULES, EXTRA_DIST): Make 'guix/build/syscalls.scm'
  conditional on BUILD_SYSCALLS_MODULE.

Merge branch 'master' into core-updates

build: Add 'generate-authors.scm' to the distribution.

* Makefile.am (EXTRA_DIST): Add build-aux/generate-authors.scm.

build: Adjust 'gen-AUTHORS' for 'distcheck' and when run from a tarball.

* Makefile.am (gen-AUTHORS): Don't do anything if '.git' is missing.  Remove
  "$(distdir)/AUTHORS" before invoking 'generate-authors.scm'.

Merge branch 'master' into core-updates

file-systems: Allow users to specify file system UUIDs as strings.

Fixes <http://bugs.gnu.org/19778>.
Reported by Mark H Weaver <mhw@netris.org>.

* gnu/system/file-systems.scm (%uuid-rx): New variable.
  (string->uuid): New procedure.
  (uuid): New macro.
* tests/file-systems.scm: New file.
* Makefile.am (SCM_TESTS): Add it.
* doc/guix.texi (File Systems): Give an example of UUID.

gnu: build: Add Linux container module.

* gnu/build/linux-container.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* .dir-locals.el: Add Scheme indent rules for 'call-with-container', and
  'container-excursion'.
* tests/containers.scm: New file.
* Makefile.am (SCM_TESTS): Add it.

build: Add 'emacs-build-system'.

* Makefile.am (MODULES): Add 'guix/build-system/emacs.scm' and
  'guix/build/emacs-build-system.scm'.
* guix/build-system/emacs.scm: New file.
* guix/build/emacs-build-system.scm: New file.
* doc/guix.texi (Build Systems): Document it.

import: Add 'elpa' importer.

* guix/import/elpa.scm: New file.
* guix/scripts/import.scm: Add "elpa" to 'importers'.
* guix/scripts/import/elpa.scm: New file.
* Makefile.am (MODULES): Add 'guix/import/elpa.scm' and
  'guix/scripts/import/elpa.scm'.
  (SCM_TESTS): Add 'tests/elpa.scm'.
* doc/guix.texi (Invoking guix import): Document it.
* tests/elpa.scm: New file.
* po/guix/POTFILES.in: Add 'guix/scripts/import/elpa.scm'.

build: Generate 'AUTHORS'.

* build-aux/generate-authors.scm: New file.
* Makefile.am (gen-AUTHORS): New target.
  (dist-hook, .PHONY): Add it.

tests: Add tests for 'guix environment'.

* tests/guix-environment.sh: New file.
* Makefile.am (SH_TESTS): Add it.