pam: add option pam.sessionVariables

modules/misc/pam.nix

@@ -6,17 +6,35 @@ let
 
   homeCfg = config.home;
 
+  vars =
+    optionalAttrs (homeCfg.sessionVariableSetter == "pam") homeCfg.sessionVariables
+    // config.pam.sessionVariables;
+
 in
 
 {
   meta.maintainers = [ maintainers.rycee ];
 
-  options = {};
+  options = {
+    pam.sessionVariables = mkOption {
+      default = {};
+      type = types.attrs;
+      example = { EDITOR = "vim"; };
+      description = ''
+        Environment variables that will be set for the PAM session.
+        The variable values must be as described in
+        <citerefentry>
+          <refentrytitle>pam_env.conf</refentrytitle>
+          <manvolnum>5</manvolnum>
+        </citerefentry>.
+      '';
+    };
+  };
 
-  config = mkIf (homeCfg.sessionVariableSetter == "pam") {
+  config = mkIf (vars != {}) {
     home.file.".pam_environment".text =
       concatStringsSep "\n" (
-        mapAttrsToList (n: v: "${n} OVERRIDE=${v}") homeCfg.sessionVariables
+        mapAttrsToList (n: v: "${n} OVERRIDE=${toString v}") vars
       ) + "\n";
   };
 }