define-obsolete-face-alias

define-obsolete-face-alias is a Lisp macro in `byte-run.el'.

(define-obsolete-face-alias OBSOLETE-FACE CURRENT-FACE WHEN)

Make OBSOLETE-FACE a face alias for CURRENT-FACE and mark it obsolete.
The string WHEN gives the Emacs version where OBSOLETE-FACE became
obsolete.