where is /usr/bin/X?

[taoist]

I've just recompiled lxdm and it works. It appears to be a library version problem.

I'll consider this closed.

[kevinthefixer]

I had a similar problem, if different error messages. There was nothing wrong with my system or with LXDM; I simply failed to start it.
$this->bbcode_second_pass_code('', 'systemctl start lxdm')
To do it on each boot:
$this->bbcode_second_pass_code('', 'systemctl enable lxdm')