revert chatwait changes in sh and acme frontends

scripts/s/sh

@@ -277,7 +277,20 @@ done; exit 1'}
 			cat $S/statewait >/dev/null >[2]/dev/null
 
 			while(! is_idle) {
-				cat $S/chatwait
+				n=`{wc -c < $S/chat >[2]/dev/null}
+				if(~ $#n 0) n=0
+				if(test $n -gt $chat_off) {
+					tail -c +`{expr $chat_off + 1} $S/chat
+					chat_off=$n
+				}
+				sleep 0.05
+			}
+
+			n=`{wc -c < $S/chat >[2]/dev/null}
+			if(~ $#n 0) n=0
+			if(test $n -gt $chat_off) {
+				tail -c +`{expr $chat_off + 1} $S/chat
+				chat_off=$n
 			}
 			printf '\n'
 	}