system: Make service procedures non-monadic.

* gnu/services/avahi.scm (configuration-file): Use 'plain-file' instead
  of 'text-file'.
  (avahi-service): Turn into a regular procedure that returns a <service>.
* gnu/services/base.scm (root-file-system-service, file-system-service,
  user-unmount-service, user-processes-service, host-name-service,
  console-keymap-service, console-font-service, mingetty-service,
  nscd.conf-file, nscd-service): Likewise.
  (%default-syslog.conf): New variable.
  (syslog-service): Use it.  Turn into a regular procedure.
  (guix-service, udev-rules-union, kvm-udev-rule, udev-service,
  device-mapping-service, swap-service): Likewise.
* gnu/services/databases.scm (%default-postgres-hba,
  %default-postgres-ident): Use 'plain-file' instead of 'text-file'.
  (%default-postgres-config): Use 'mixed-text-file' instead of
  'text-file*'.
  (postgresql-service):  Use 'program-file' instead of 'gexp->script'.
  Turn into a regular procedure.
* gnu/services/desktop.scm (dbus-configuration-directory): Use
  'computed-file' instead of 'gexp->derivation'.
  (upower-configuration-file, geoclue-configuration-file,
  elogind-configuration-file): Use 'plain-file' instead of 'text-file'.
  (dbus-service, upower-service, colord-service, geoclue-service,
  polkit-service, elogind-service): Turn into regular procedures.
  (%desktop-services): Remove use of 'mlet' when iterating on
  %BASE-SERVICES.
* gnu/services/lirc.scm (lirc-service): Turn into a regular procedure.
* gnu/services/networking.scm (static-networking-service,
  dhcp-client-service, ntp-service, tor-service, bitlbee-service,
  wicd-service): Likewise.
* gnu/services/ssh.scm (lsh-service): Likewise.
* gnu/services/web.scm (nginx-service): Likewise.
* gnu/services/xorg.scm (xorg-configuration-file): Use 'mixed-text-file'
  instead of 'text-file*'.
  (xorg-start-command, slim-service): Turn into regular procedures.
  (xinitrc): Use 'program-file' instead of 'gexp->script'.
* gnu/system/install.scm (cow-store-service,
  configuration-template-service): Turn into regular procedures.
* gnu/system.scm (other-file-system-services, device-mapping-services,
  swap-services, essential-services, operating-system-services,
  user-shells, operating-system-accounts): Remove now unnecessary
  'mlet' and turn into regular procedures.
  (operating-system-etc-directory, operating-system-activation-script,
  operating-system-boot-script): Adjust accordingly.
* doc/guix.texi (Base Services, Networking Services, X Window, Desktop
  Services, Database Services, Web Services, Various Services, Name
  Service Switch): Adjust accordingly.

gnu/services/lirc.scm

@@ -19,7 +19,6 @@
 (define-module (gnu services lirc)
   #:use-module (gnu services)
   #:use-module (gnu packages lirc)
-  #:use-module (guix monads)
   #:use-module (guix store)
   #:use-module (guix gexp)
   #:export (lirc-service))
@@ -41,28 +40,26 @@ The daemon will use specified @var{device}, @var{driver} and
 
 Finally, @var{extra-options} is a list of additional command-line options
 passed to @command{lircd}."
-  (with-monad %store-monad
-    (return
-     (service
-      (provision '(lircd))
-      (documentation "Run the LIRC daemon.")
-      (requirement '(user-processes))
-      (start #~(make-forkexec-constructor
-                (list (string-append #$lirc "/sbin/lircd")
-                      "--nodaemon"
-                      #$@(if device
-                             #~("--device" #$device)
-                             #~())
-                      #$@(if driver
-                             #~("--driver" #$driver)
-                             #~())
-                      #$@(if config-file
-                             #~(#$config-file)
-                             #~())
-                      #$@extra-options)))
-      (stop #~(make-kill-destructor))
-      (activate #~(begin
-                    (use-modules (guix build utils))
-                    (mkdir-p "/var/run/lirc")))))))
+  (service
+   (provision '(lircd))
+   (documentation "Run the LIRC daemon.")
+   (requirement '(user-processes))
+   (start #~(make-forkexec-constructor
+             (list (string-append #$lirc "/sbin/lircd")
+                   "--nodaemon"
+                   #$@(if device
+                          #~("--device" #$device)
+                          #~())
+                   #$@(if driver
+                          #~("--driver" #$driver)
+                          #~())
+                   #$@(if config-file
+                          #~(#$config-file)
+                          #~())
+                   #$@extra-options)))
+   (stop #~(make-kill-destructor))
+   (activate #~(begin
+                 (use-modules (guix build utils))
+                 (mkdir-p "/var/run/lirc")))))
 
 ;;; lirc.scm ends here