vmware-guest: fix vmmouse driver

Fix automatic mouse grabbing/releasing when running as a vmware guest.

1. The xf86inputvmmouse is not loaded by default. Add it.
2. InptutDevice sections for which specify a driver are ignored if
AutoAddDevices is enabled (which it is by default). See [1]. Instead use
an InputClass to load the vmmouse driver.

[1] https://www.x.org/archive/X11R7.7/doc/man/man5/xorg.conf.5.xhtml#heading8

nixos/modules/virtualisation/vmware-guest.nix

@@ -5,6 +5,7 @@ with lib;
 let
   cfg = config.services.vmwareGuest;
   open-vm-tools = pkgs.open-vm-tools;
+  xf86inputvmmouse = pkgs.xorg.xf86inputvmmouse;
 in
 {
   options = {
@@ -29,18 +30,17 @@ in
 
     services.xserver = {
       videoDrivers = mkOverride 50 [ "vmware" ];
+      modules = [ xf86inputvmmouse ];
 
       config = ''
-          Section "InputDevice"
+          Section "InputClass"
             Identifier "VMMouse"
+            MatchDevicePath "/dev/input/event*"
+            MatchProduct "ImPS/2 Generic Wheel Mouse"
             Driver "vmmouse"
           EndSection
         '';
 
-      serverLayoutSection = ''
-          InputDevice "VMMouse"
-        '';
-
       displayManager.sessionCommands = ''
           ${open-vm-tools}/bin/vmware-user-suid-wrapper
         '';