bin/52359: Command line editing broken in tmux

[ben@pocket.services]

>Number:         52359
>Category:       bin
>Synopsis:       Going back in history screws up terminal view in tmux
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 02 11:15:00 +0000 2017
>Originator:     Benjamin Lorenz
>Release:        NetBSD 8.99.1
>Organization:
	
>Environment:
	
	
System: NetBSD hermes.lorenz.place 8.99.1 NetBSD 8.99.1 (RPI2) #1: Sat Jul 1 14:10:03 CEST 2017 bjjl@hermes.lorenz.place:/home/bjjl/obj/sys/arch/evbarm/compile/RPI2 evbarm
Architecture: earmv7hf
Machine: evbarm
>Description:
	When changing screen resolution, and then using the history function
	of the interactive shell, the view gets screwed up.
>How-To-Repeat:
	1. Start tmux. Enter one command, say, `uptime'.
	2. Enlarge or shrink the terminal window vertically
	   (change the number of lines the terminal window can display)
	3. Press `cursor-up' key to get back to the last command
	4. You will see the prompt being displayed twice; in my case
	   it looks like "hermes$ hermes$ uptime". 

	Especially for commands that span over two lines, this is highly
	confusing and annoying. Cross-checking with NetBSD 7.1, this
	problem does not exist yet.
>Fix:
	

>Unformatted: