Fix utempter

[leahneukirchen]

utempter was not installed setgid utmp, so it didn't work.

Enable utempter for screen and tmux.

ping @sgn and @steinex.

Testing the changes

• I tested the changes in this PR: YES*

[sbromberger]

ref #40972

[vincele]

I think I have this problem:

$ screen /dev/ttyUSB0 1500000
/dev/null/utmp: Not a directory
[screen is terminating]
$ screen -ln /dev/ttyUSB0 1500000
/dev/null/utmp: Not a directory
[screen is terminating]
$ screen -l /dev/ttyUSB0 1500000
/dev/null/utmp: Not a directory
[screen is terminating]

But nor -l nor -ln seem to have any effect on that. I may have misunderstood their intent, though.

       -l and -ln
            turns login mode on or off (for /etc/utmp updating).  This can
            also be defined through the deflogin .screenrc command.

My screen version is still at 4.9.0_1

$ xbps-query screen
architecture: x86_64-musl
build-options: ~multiuser 
conf_files:
	/etc/screenrc
	/etc/skel/.screenrc
filename-sha256: 2434acac0bbcc05aa899b470d8e34b23b9c5a9f51d5d59b1562f5628708ef778
filename-size: 557KB
homepage: http://www.gnu.org/s/screen/
install-date: 2022-12-12 22:34 CET
install-script: 688B
installed_size: 898KB
license: GPL-3.0-or-later
maintainer: Frank Steinborn 
metafile-sha256: c9352d316e60e03d78309afcc84e3704c4e8fdcb6aaeb0f90e49409a5ba5bdde
pkgname: screen
pkgver: screen-4.9.0_1
repository: https://repo-default.voidlinux.org/current/musl
run_depends:
	ncurses-libs>=5.8_1
	pam-libs>=1.1.6_3
	musl>=1.1.24_7
shlib-requires:
	libncursesw.so.6
	libpam.so.0
	libc.so
short_desc: GNU screen manager with VT100/ANSI terminal emulation
source-revisions: screen:217a65562c
state: installed

My naive question is: wouldn't it make sense to compile screen without utmp support ?

EDIT:
That may not be as easy as I thought:

$ ./xbps-src show-options screen
=> screen-4.9.0_1: the following build options are set:
   multiuser:  (OFF)

[vincele]

The new version does not have this problem any more.
Thanks @leahneukirchen