system: Use 'file-append' to denote file names.

* gnu/services/avahi.scm, gnu/services/base.scm,
gnu/services/databases.scm, gnu/services/dbus.scm,
gnu/services/desktop.scm, gnu/services/dict.scm,
gnu/services/mail.scm, gnu/services/networking.scm,
gnu/services/sddm.scm, gnu/services/spice.scm,
gnu/services/ssh.scm, gnu/services/web.scm,
gnu/services/xorg.scm, gnu/system.scm: Replace the
 #~(string-append #$pkg "/bin/foo") idiom with
 (file-append pkg "/bin/foo").

gnu/services/avahi.scm

@@ -88,7 +88,7 @@ (define %avahi-accounts
          (system? #t)
          (comment "Avahi daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define %avahi-activation
   ;; Activation gexp.

gnu/services/base.scm

@@ -516,7 +516,7 @@ (define rng-tools (rngd-configuration-rng-tools config))
       (define device (rngd-configuration-device config))
 
       (define rngd-command
-        (list #~(string-append #$rng-tools "/sbin/rngd")
+        (list (file-append rng-tools "/sbin/rngd")
               "-f" "-r" device))
 
       (shepherd-service
@@ -893,7 +893,7 @@ (define-record-type* <syslog-configuration>
   syslog-configuration  make-syslog-configuration
   syslog-configuration?
   (syslogd              syslog-configuration-syslogd
-                        (default #~(string-append #$inetutils "/libexec/syslogd")))
+                        (default (file-append inetutils "/libexec/syslogd")))
   (config-file          syslog-configuration-config-file
                         (default %default-syslog.conf)))
 
@@ -1009,7 +1009,7 @@ (define* (guix-build-accounts count #:key
 
              (comment (format #f "Guix Build User ~2d" n))
              (home-directory "/var/empty")
-             (shell #~(string-append #$shadow "/sbin/nologin"))))
+             (shell (file-append shadow "/sbin/nologin"))))
           1+
           1))
 
@@ -1036,7 +1036,7 @@ (define (hydra-key-authorization key guix)
 
 (define %default-authorized-guix-keys
   ;; List of authorized substitute keys.
-  (list #~(string-append #$guix "/share/guix/hydra.gnu.org.pub")))
+  (list (file-append guix "/share/guix/hydra.gnu.org.pub")))
 
 (define-record-type* <guix-configuration>
   guix-configuration make-guix-configuration
@@ -1167,7 +1167,7 @@ (define %guix-publish-accounts
          (system? #t)
          (comment "guix publish user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define guix-publish-service-type
   (service-type (name 'guix-publish)

gnu/services/databases.scm

@@ -76,7 +76,7 @@ (define %postgresql-accounts
          (system? #t)
          (comment "PostgreSQL server user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define postgresql-activation
   (match-lambda
@@ -171,7 +171,7 @@ (define %mysql-accounts
          (group "mysql")
          (system? #t)
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define mysql-configuration-file
   (match-lambda

gnu/services/dbus.scm

@@ -128,13 +128,13 @@ (define %dbus-accounts
          (system? #t)
          (comment "D-Bus system bus user")
          (home-directory "/var/run/dbus")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define dbus-setuid-programs
   ;; Return the file name of the setuid program that we need.
   (match-lambda
     (($ <dbus-configuration> dbus services)
-     (list #~(string-append #$dbus "/libexec/dbus-daemon-launch-helper")))))
+     (list (file-append dbus "/libexec/dbus-daemon-launch-helper")))))
 
 (define (dbus-activation config)
   "Return an activation gexp for D-Bus using @var{config}."

gnu/services/desktop.scm

@@ -460,9 +460,8 @@ (define polkit-etc-files
 (define polkit-setuid-programs
   (match-lambda
     (($ <polkit-configuration> polkit)
-     (list #~(string-append #$polkit
-                            "/lib/polkit-1/polkit-agent-helper-1")
-           #~(string-append #$polkit "/bin/pkexec")))))
+     (list (file-append polkit "/lib/polkit-1/polkit-agent-helper-1")
+           (file-append polkit "/bin/pkexec")))))
 
 (define polkit-service-type
   (service-type (name 'polkit)
@@ -522,7 +521,7 @@ (define %colord-accounts
          (system? #t)
          (comment "colord daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define colord-service-type
   (service-type (name 'colord)
@@ -738,8 +737,8 @@ (define (pam-extension-procedure config)
   (define pam-elogind
     (pam-entry
      (control "required")
-     (module #~(string-append #$(elogind-package config)
-                              "/lib/security/pam_elogind.so"))))
+     (module (file-append (elogind-package config)
+                          "/lib/security/pam_elogind.so"))))
 
   (list (lambda (pam)
           (pam-service

gnu/services/dict.scm

@@ -73,7 +73,7 @@ (define %dicod-accounts
          (group "dicod")
          (system? #t)
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define (dicod-configuration-file config)
   (define database->text

gnu/services/mail.scm

@@ -1505,7 +1505,7 @@ (define %dovecot-accounts
          (system? #t)
          (comment "Dovecot daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))
+         (shell (file-append shadow "/sbin/nologin")))
 
         (user-group (name "dovenull") (system? #t))
         (user-account
@@ -1514,7 +1514,7 @@ (define %dovecot-accounts
          (system? #t)
          (comment "Dovecot daemon login user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define %dovecot-activation
   ;; Activation gexp.

gnu/services/networking.scm

@@ -194,7 +194,7 @@ (define dhcp-client-service-type
    'dhcp-client
    (lambda (dhcp)
      (define dhclient
-       #~(string-append #$dhcp "/sbin/dhclient"))
+       (file-append dhcp "/sbin/dhclient"))
 
      (define pid-file
        "/var/run/dhclient.pid")
@@ -306,7 +306,7 @@ (define %ntp-accounts
          (system? #t)
          (comment "NTP daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 
 (define (ntp-service-activation config)
@@ -361,7 +361,7 @@ (define %tor-accounts
          (system? #t)
          (comment "Tor daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define-record-type <hidden-service>
   (hidden-service name mapping)
@@ -554,7 +554,7 @@ (define %bitlbee-accounts
          (system? #t)
          (comment "BitlBee daemon user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define %bitlbee-activation
   ;; Activation gexp for BitlBee.

gnu/services/sddm.scm

@@ -48,9 +48,9 @@ (define-record-type* <sddm-configuration>
   (numlock                sddm-configuration-numlock
                           (default "on"))
   (halt-command           sddm-configuration-halt-command
-                          (default #~(string-append #$shepherd "/sbin/halt")))
+                          (default (file-append shepherd "/sbin/halt")))
   (reboot-command         sddm-configuration-reboot-command
-                          (default #~(string-append #$shepherd "/sbin/reboot")))
+                          (default (file-append shepherd "/sbin/reboot")))
 
   ;; [Theme]
   ;; valid values are elarun or maldives
@@ -75,24 +75,24 @@ (define-record-type* <sddm-configuration>
   (hide-users             sddm-configuration-hide-users
                           (default ""))
   (hide-shells            sddm-configuration-hide-shells
-                          (default #~(string-append #$shadow "/sbin/nologin")))
+                          (default (file-append shadow "/sbin/nologin")))
 
   ;; [Wayland]
   (session-command        sddm-configuration-session-command
-                          (default #~(string-append #$sddm "/share/sddm/scripts/wayland-session")))
+                          (default (file-append sddm "/share/sddm/scripts/wayland-session")))
   (sessions-directory     sddm-configuration-sessions-directory
                           (default "/run/current-system/profile/share/wayland-sessions"))
   ;; [X11]
   (xorg-server-path       sddm-configuration-xorg-server-path
                           (default (xorg-start-command)))
   (xauth-path             sddm-configuration-xauth-path
-                          (default #~(string-append #$xauth "/bin/xauth")))
+                          (default (file-append xauth "/bin/xauth")))
   (xephyr-path            sddm-configuration-xephyr-path
-                          (default #~(string-append #$xorg-server "/bin/Xephyr")))
+                          (default (file-append xorg-server "/bin/Xephyr")))
   (xdisplay-start         sddm-configuration-xdisplay-start
-                          (default #~(string-append #$sddm "/share/sddm/scripts/Xsetup")))
+                          (default (file-append sddm "/share/sddm/scripts/Xsetup")))
   (xdisplay-stop          sddm-configuration-xdisplay-stop
-                          (default #~(string-append #$sddm "/share/sddm/scripts/Xstop")))
+                          (default (file-append sddm "/share/sddm/scripts/Xstop")))
   (xsession-command       sddm-configuration-xsession-command
                           (default (xinitrc)))
   (xsessions-directory    sddm-configuration-xsessions-directory
@@ -292,7 +292,7 @@ (define %sddm-accounts
          (system? #t)
          (comment "SDDM user")
          (home-directory "/var/lib/sddm")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 ;; Add default themes to profile
 (define sddm-profile-service

gnu/services/spice.scm

@@ -43,7 +43,7 @@ (define spice-vdagent (spice-vdagent-configuration-spice-vdagent config))
 
   (define spice-vdagentd-command
     (list
-      #~(string-append #$spice-vdagent "/sbin/spice-vdagentd")
+      (file-append spice-vdagent "/sbin/spice-vdagentd")
       "-x"))
 
   (list

gnu/services/ssh.scm

@@ -122,7 +122,7 @@ (define interfaces (lsh-configuration-interfaces config))
 
   (define lsh-command
     (append
-     (cons #~(string-append #$lsh "/sbin/lshd")
+     (cons (file-append lsh "/sbin/lshd")
            (if daemonic?
                (let ((syslog (if (lsh-configuration-syslog-output? config)
                                  '()

gnu/services/web.scm

@@ -67,7 +67,7 @@ (define %nginx-accounts
          (system? #t)
          (comment "nginx server user")
          (home-directory "/var/empty")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+         (shell (file-append shadow "/sbin/nologin")))))
 
 (define nginx-activation
   (match-lambda
@@ -86,7 +86,7 @@ (define nginx-activation
 (define nginx-shepherd-service
   (match-lambda
     (($ <nginx-configuration> nginx log-directory run-directory config-file)
-     (let* ((nginx-binary #~(string-append #$nginx "/sbin/nginx"))
+     (let* ((nginx-binary (file-append nginx "/sbin/nginx"))
             (nginx-action
              (lambda args
                #~(lambda _

gnu/services/xorg.scm

@@ -267,7 +267,7 @@ (define (exec-from-login-shell command . args)
 
 (define %default-slim-theme
   ;; Theme based on work by Felipe López.
-  #~(string-append #$%artwork-repository "/slim"))
+  (file-append %artwork-repository "/slim"))
 
 (define %default-slim-theme-name
   ;; This must be the name of the sub-directory in %DEFAULT-SLIM-THEME that
@@ -374,8 +374,8 @@ (define* (slim-service #:key (slim slim)
                        (theme %default-slim-theme)
                        (theme-name %default-slim-theme-name)
                        (xauth xauth) (shepherd shepherd) (bash bash)
-                       (auto-login-session #~(string-append #$windowmaker
-                                                            "/bin/wmaker"))
+                       (auto-login-session (file-append windowmaker
+                                                        "/bin/wmaker"))
                        (startx (xorg-start-command)))
   "Return a service that spawns the SLiM graphical login manager, which in
 turn starts the X display server with @var{startx}, a command as returned by
@@ -450,14 +450,13 @@ (define* (screen-locker-service package
 for it.  For example:
 
 @lisp
-(screen-locker-service xlockmore \"xlock\")
+ (screen-locker-service xlockmore \"xlock\")
 @end lisp
 
 makes the good ol' XlockMore usable."
   (service screen-locker-service-type
            (screen-locker program
-                          #~(string-append #$package
-                                           #$(string-append "/bin/" program))
+                          (file-append package "/bin/" program)
                           allow-empty-passwords?)))
 
 ;;; xorg.scm ends here

gnu/system.scm

@@ -472,9 +472,9 @@ (define* (operating-system-etc-service os)
   source /run/current-system/profile/etc/profile.d/bash_completion.sh
 fi\n")))
     (etc-service
-     `(("services" ,#~(string-append #$net-base "/etc/services"))
-       ("protocols" ,#~(string-append #$net-base "/etc/protocols"))
-       ("rpc" ,#~(string-append #$net-base "/etc/rpc"))
+     `(("services" ,(file-append net-base "/etc/services"))
+       ("protocols" ,(file-append net-base "/etc/protocols"))
+       ("rpc" ,(file-append net-base "/etc/rpc"))
        ("login.defs" ,#~#$login.defs)
        ("issue" ,#~#$issue)
        ("nsswitch.conf" ,#~#$nsswitch)
@@ -482,8 +482,8 @@ (define* (operating-system-etc-service os)
        ("bashrc" ,#~#$bashrc)
        ("hosts" ,#~#$(or (operating-system-hosts-file os)
                          (default-/etc/hosts (operating-system-host-name os))))
-       ("localtime" ,#~(string-append #$tzdata "/share/zoneinfo/"
-                                      #$(operating-system-timezone os)))
+       ("localtime" ,(file-append tzdata "/share/zoneinfo/"
+                                  (operating-system-timezone os)))
        ("sudoers" ,(operating-system-sudoers-file os))))))
 
 (define %root-account
@@ -547,7 +547,7 @@ (define (operating-system-environment-variables os)
 @var{session-environment-service-type}, to be used in @file{/etc/environment}."
   `(("LANG" . ,(operating-system-locale os))
     ("TZ" . ,(operating-system-timezone os))
-    ("TZDIR" . ,#~(string-append #$tzdata "/share/zoneinfo"))
+    ("TZDIR" . ,(file-append tzdata "/share/zoneinfo"))
     ;; Tell 'modprobe' & co. where to look for modules.
     ("LINUX_MODULE_DIRECTORY" . "/run/booted-system/kernel/lib/modules")
     ;; These variables are honored by OpenSSL (libssl) and Git.
@@ -571,12 +571,12 @@ (define (operating-system-environment-variables os)
 (define %setuid-programs
   ;; Default set of setuid-root programs.
   (let ((shadow (@ (gnu packages admin) shadow)))
-    (list #~(string-append #$shadow "/bin/passwd")
-          #~(string-append #$shadow "/bin/su")
-          #~(string-append #$inetutils "/bin/ping")
-          #~(string-append #$inetutils "/bin/ping6")
-          #~(string-append #$sudo "/bin/sudo")
-          #~(string-append #$fuse "/bin/fusermount"))))
+    (list (file-append shadow "/bin/passwd")
+          (file-append shadow "/bin/su")
+          (file-append inetutils "/bin/ping")
+          (file-append inetutils "/bin/ping6")
+          (file-append sudo "/bin/sudo")
+          (file-append fuse "/bin/fusermount"))))
 
 (define %sudoers-specification
   ;; Default /etc/sudoers contents: 'root' and all members of the 'wheel'