merged height. If FROM is an invalid height, then INVALID is
returned instead. FROM and TO may be either absolute face heights or
`relative' heights; the returned value is always an absolute height
- unless both FROM and TO are relative. GCPRO is a lisp value that
- will be protected from garbage-collection if this function makes a
- call into lisp. */
+ unless both FROM and TO are relative. */
Lisp_Object
merge_face_heights (from, to, invalid)