systemd.sockets: Add listenStreams option for specifying several sockets

modules/system/boot/systemd-unit-options.nix

@@ -215,6 +215,16 @@ rec {
 
   socketOptions = unitOptions // {
 
+    listenStreams = mkOption {
+      default = [];
+      types = types.listOf types.string;
+      example = [ "0.0.0.0:993" "/run/my-socket" ];
+      description = ''
+        For each item in this list, a <literal>ListenStream</literal>
+        option in the <literal>[Socket]</literal> section will be created.
+      '';
+    };
+
     socketConfig = mkOption {
       default = {};
       example = { ListenStream = "/run/my-socket"; };

modules/system/boot/systemd.nix

@@ -275,6 +275,7 @@ let
 
           [Socket]
           ${attrsToSection def.socketConfig}
+          ${concatStringsSep "\n" (map (s: "ListenStream=${s}") def.listenStreams)}
         '';
     };