units: use `systemctl exit` to kill the user manager (#8648)

Use `systemctl --user --force exit` to implement the systemd-exit
user service.

This removes our dependence on an external `kill` binary and the
concerns about whether they recognize SIGRTMIN+n by name or what their
interpretation of SIGRTMIN is.

Tested: `systemctl --user start systemd-exit.service` kills the
  `systemd --user` instance for my user.

diff --git a/meson.build b/meson.build
index b1d178ad1de1f79c4a250f75b6499d945fc17fff..6917001f9370f35ca579f46588f01d3ac1dfded1 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -640,7 +640,6 @@ mkdir_p = 'mkdir -p $DESTDIR/@0@'
 #if 0 /// elogind has a bit different list and some adaptions
 # progs = [['quotaon',    '/usr/sbin/quotaon'    ],
 #          ['quotacheck', '/usr/sbin/quotacheck' ],
-#          ['kill',       '/usr/bin/kill'        ],
 #          ['kmod',       '/usr/bin/kmod'        ],
 #          ['kexec',      '/usr/sbin/kexec'      ],
 #          ['sulogin',    '/usr/sbin/sulogin'    ],