The xorg modules are used inside of services that's thunked. So we can
make them depend on the %current-system.
* gnu/services/xorg.scm
(default-xorg-modules): New variable.
(%default-xorg-modules): Return result of (default-xorg-modules).
Change-Id: I10f722e52d598ce3e83ef3f200b3bd953bc08e17
Signed-off-by: Rutherther <rutherther@ditigal.xyz>