bin/59171: tmux-3.5a doesn't create utmp entries for sessions

[rvp%SDF.ORG@localhost]

>Number:         59171
>Category:       bin
>Synopsis:       tmux-3.5a doesn't create utmp entries for sessions
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 12 00:35:00 +0000 2025
>Originator:     RVP
>Release:        NetBSD/amd64 10.99.12
>Organization:
>Environment:
NetBSD/amd64 10.99.12
>Description:
tmux-3.5a doesn't create utmp entries anymore due to `-DHAVE_UTEMPTER=1'
getting lost in:

cvs rdiff -u -r1.29 -r1.30 src/external/bsd/tmux/usr.bin/tmux/Makefile


>How-To-Repeat:
Start tmux(1) in -HEAD (problem not present in 10.x, or 9.x), then
run who(1). Create a new window with Ctrl-b c; type `who' again.

Notice the lack of entries for the PTYs.
>Fix:
Add back `-DHAVE_UTEMPTER=1'