Bug#230537: xdm: warn of unused Identifiers

[Dan Jacobson]

Package: xdm
Version: 4.2.1-14
Severity: wishlist

In /var/log/XFree86.0.log there could be warnings/notices about
Identifiers declared, but then never used in ServerLayout, e.g.:
(II) ... Identifier "ZZ" declared, but then never used in ServerLayout
(II) ... Identifier "ZZ" unused in ServerLayout