services: Move 'session-environment-service-type' to pam.scm.

* gnu/services/base.scm (environment-variables->environment-file)
(session-environment-service-type)
(session-environment-service): Move to...
* gnu/system/pam.scm: ... here.

gnu/services/base.scm

@@ -59,8 +59,6 @@
             user-unmount-service
             swap-service
             user-processes-service
-            session-environment-service
-            session-environment-service-type
             host-name-service
             console-keymap-service
             %default-console-font
@@ -600,47 +598,6 @@ to add @var{device} to the kernel's entropy pool.  The service will fail if
             (rng-tools rng-tools)
             (device device))))
 
-
-;;;
-;;; System-wide environment variables.
-;;;
-
-(define (environment-variables->environment-file vars)
-  "Return a file for pam_env(8) that contains environment variables VARS."
-  (apply mixed-text-file "environment"
-         (append-map (match-lambda
-                       ((key . value)
-                        (list key "=" value "\n")))
-                     vars)))
-
-(define session-environment-service-type
-  (service-type
-   (name 'session-environment)
-   (extensions
-    (list (service-extension
-           etc-service-type
-           (lambda (vars)
-             (list `("environment"
-                     ,(environment-variables->environment-file vars)))))))
-   (compose concatenate)
-   (extend append)
-   (description
-    "Populate @file{/etc/environment} with the specified environment
-variables.  The value of this service is a list of name/value pairs for
-environments variables, such as:
-
-@example
-'((\"TZ\" . \"Canada/Pacific\"))
-@end example\n")))
-
-(define (session-environment-service vars)
-  "Return a service that builds the @file{/etc/environment}, which can be read
-by PAM-aware applications to set environment variables for sessions.
-
-VARS should be an association list in which both the keys and the values are
-strings or string-valued gexps."
-  (service session-environment-service-type vars))
-
 
 ;;;
 ;;; Console & co.

gnu/system/pam.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -50,6 +50,9 @@
             unix-pam-service
             base-pam-services
 
+            session-environment-service
+            session-environment-service-type
+
             pam-root-service-type
             pam-root-service))
 
@@ -276,6 +279,48 @@ authenticate to run COMMAND."
                '("useradd" "userdel" "usermod"
                  "groupadd" "groupdel" "groupmod"))))
 
+
+;;;
+;;; System-wide environment variables.
+;;;
+
+(define (environment-variables->environment-file vars)
+  "Return a file for pam_env(8) that contains environment variables VARS."
+  (apply mixed-text-file "environment"
+         (append-map (match-lambda
+                       ((key . value)
+                        (list key "=" value "\n")))
+                     vars)))
+
+(define session-environment-service-type
+  (service-type
+   (name 'session-environment)
+   (extensions
+    (list (service-extension
+           etc-service-type
+           (lambda (vars)
+             (list `("environment"
+                     ,(environment-variables->environment-file vars)))))))
+   (compose concatenate)
+   (extend append)
+   (description
+    "Populate @file{/etc/environment}, which is honored by @code{pam_env},
+with the specified environment variables.  The value of this service is a list
+of name/value pairs for environments variables, such as:
+
+@example
+'((\"TZ\" . \"Canada/Pacific\"))
+@end example\n")))
+
+(define (session-environment-service vars)
+  "Return a service that builds the @file{/etc/environment}, which can be read
+by PAM-aware applications to set environment variables for sessions.
+
+VARS should be an association list in which both the keys and the values are
+strings or string-valued gexps."
+  (service session-environment-service-type vars))
+
+
 
 ;;;
 ;;; PAM root service.