+;;; FIXME: We probably want to rename the accessor MUTEX-OWNER.
+(defun mutex-value (mutex)
+ "Current owner of the mutex, NIL if the mutex is free."
+ (mutex-%owner mutex))
+
+(defsetf mutex-value set-mutex-value)
+
+(declaim (inline set-mutex-value))
+(defun set-mutex-value (mutex value)
+ (declare (ignore mutex value))
+ (error "~S is no longer supported." '(setf mutex-value)))
+
+(define-compiler-macro set-mutex-value (&whole form mutex value)
+ (declare (ignore mutex value))
+ (warn "~S is no longer supported, and will signal an error at runtime."
+ '(setf mutex-value))
+ form)
+