dwm: add extraSessionCommands option (NixOS#267471)

Author: fpletz

nixos/modules/services/x11/window-managers/dwm.nix

@@ -6,15 +6,20 @@ let
 
   cfg = config.services.xserver.windowManager.dwm;
 
-in
-
-{
+in {
 
   ###### interface
 
   options = {
     services.xserver.windowManager.dwm = {
       enable = mkEnableOption "dwm";
+      extraSessionCommands = mkOption {
+        default = "";
+        type = types.lines;
+        description = ''
+          Shell commands executed just before dwm is started.
+        '';
+      };
       package = mkPackageOption pkgs "dwm" {
         example = ''
           pkgs.dwm.overrideAttrs (oldAttrs: rec {
@@ -30,20 +35,20 @@ in
     };
   };
 
-
   ###### implementation
 
   config = mkIf cfg.enable {
 
-    services.xserver.windowManager.session = singleton
-      { name = "dwm";
-        start =
-          ''
-            export _JAVA_AWT_WM_NONREPARENTING=1
-            dwm &
-            waitPID=$!
-          '';
-      };
+    services.xserver.windowManager.session = singleton {
+      name = "dwm";
+      start = ''
+        ${cfg.extraSessionCommands}
+
+        export _JAVA_AWT_WM_NONREPARENTING=1
+        dwm &
+        waitPID=$!
+      '';
+    };
 
     environment.systemPackages = [ cfg.package ];