* gnu/services/desktop.scm
(desktop-services-for-system): Use gdm on all 64-bit systems.
* gnu/services/xorg.scm (set-xorg-configuration): Adapt to
desktop-services-for-system change.
* gnu/system/examples/desktop.tmpl: Determine the support of Gnome by checking
for supported package.
Fixes: #5388
Change-Id: I0d512a7c31188cea0335e66f00a6d65ae59d09a4
Signed-off-by: Rutherther <rutherther@ditigal.xyz>