Function: make-obsolete-variable

Make the byte-compiler warn that OBSOLETE-NAME is obsolete.
The warning will say that CURRENT-NAME should be used instead.
If CURRENT-NAME is a string, that is the `use instead' message.
WHEN should be a string indicating when the variable
was first made obsolete, for example a date or a release number.
ACCESS-TYPE if non-nil should specify the kind of access that will trigger
obsolescence warnings; it can be either `get' or `set'.

(fn OBSOLETE-NAME CURRENT-NAME &optional WHEN ACCESS-TYPE)