X-resource-get -- Get X resource specified by NAME and XCLASS from Xrm database.
(X-resource-get name #&optional xclass)
Get X resource specified by name and xclass from Xrm database.
Both name and xclass are strings, as is the returned value. If
xclass is omitted, it defaults to the same string as name.
If there is no resource under the given key, #f is returned.