[MacPorts] #61919: garbled statusline in Big Sur

[MacPorts]

#61919: garbled statusline in Big Sur
-------------------------------+--------------------
 Reporter:  arjanvandervelde   |      Owner:  (none)
     Type:  defect             |     Status:  new
 Priority:  Normal             |  Milestone:
Component:  ports              |    Version:  2.6.4
 Keywords:  statusline bigsur  |       Port:  screen
-------------------------------+--------------------
 Hi!

 I'm running into a strange issue with GNU screen built on Big Sur (intel).
 For some reason it does not correctly show the statusline. A binary
 compiled on last MacOS before Big Sur (same macports commit) works fine.
 I'm using the following screenrc:

 startup_message off
 mousetrack on
 defmousetrack on
 logfile /Users/vanderva/log/screenlogs/screenlog.%n
 shell -/bin/bash
 shelltitle shell
 hardstatus on
 hardstatus alwayslastline '%{= kK}[ %{G}%H %{K}][ %{G}%h %{K}][ %= %{=
 kw}%?%-Lw%?%{B}(%{W}%n*%f %t%?(%u)%?%{B})%{w}%?%+Lw%?%?%= %{K}%{B} %{w} ][
 %l ][ %d %M %c ]%{K}'
 defutf8 on
 defscrollback 99999
 msgwait 3
 deflog on
 logtstamp on
 logtstamp after 3600
 screen -t "mac" 0
 log on
 bind '+' resize
 caption string "%?%F%{.R.}%?%3n %t%? [%h]%?"
 layout save default
 altscreen on
 vbell off

 see screenshots attached.

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Ticket URL: <https://trac.macports.org/ticket/61919>
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