services: Use more 'file-append'.

* gnu/services/authentication.scm (pam-ldap-pam-service): Use
'file-append' instead of #~(string-append ...).
* gnu/services/base.scm (greetd-pam-service): Likewise.
* gnu/services/kerberos.scm (pam-krb5-pam-service): Likewise.
* gnu/services/pam-mount.scm (pam-mount-pam-service): Likewise.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/gnu/services/pam-mount.scm b/gnu/services/pam-mount.scm
index dbb9d0285f7..b3a02e82e92 100644
--- a/gnu/services/pam-mount.scm
+++ b/gnu/services/pam-mount.scm
@@ -94,7 +94,7 @@
   (define optional-pam-mount
     (pam-entry
      (control "optional")
-     (module #~(string-append #$pam-mount "/lib/security/pam_mount.so"))))
+     (module (file-append pam-mount "/lib/security/pam_mount.so"))))
   (list
    (pam-extension
     (transformer