Changes the option and explicitely sets it for each desktopManager.
Reasoning: Currently,
services.xserver.displayManager.desktopManagerHandlesLidAndPower is set
to true by default. This creates a problem for users without desktop
environments activated, since lid management simply doesn't work
(and they have to be lucky to find this option).
See issue #9671
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
Naïm Favier