Merge pull request #7019 from Citadel-Station-13/upstream-merge-38193

[MIRROR] Turns /datum.isprocessing into a datum flag

code/game/objects/structures/beds_chairs/chair.dm

@@ -385,7 +385,7 @@
 	turns = 0
 	if(!istype(user) || !user.canUseTopic(src, BE_CLOSE, ismonkey(user)))
 		return
-	if(!isprocessing)
+	if(!(datum_flags & DF_ISPROCESSING))
 		user.visible_message("<span class='notice'>[user] spins [src] around, and Ratvarian technology keeps it spinning FOREVER.</span>", \
 		"<span class='notice'>Automated spinny chairs. The pinnacle of Ratvarian technology.</span>")
 		START_PROCESSING(SSfastprocess, src)