have to use X11 for Vivado :(

modules/nixos-common.nix

@@ -131,6 +131,28 @@
 
   gtk.iconCache.enable = true;
 
+  environment.pathsToLink = [ "/libexec" ];
+  services.xserver = {
+    enable = true;
+
+    desktopManager = {
+      xterm.enable = false;
+    };
+   
+    displayManager = {
+        defaultSession = "none+i3";
+    };
+
+    windowManager.i3 = {
+      enable = true;
+      extraPackages = with pkgs; [
+        dmenu #application launcher most people use
+        i3status # gives you the default i3 status bar
+        i3lock #default i3 screen locker
+     ];
+    };
+  };
+
   # ------------ Graphics ------------
 
   hardware.opengl = {