pull upstream changes from gitstatus

gitstatus/gitstatus.plugin.zsh

@@ -356,7 +356,9 @@ function gitstatus_start() {
         ${(q)daemon}-static $daemon_args
       fi
       echo -nE $'bye\x1f0\x1e'"
-    cmd="${commands[setsid]:-} zsh -dfxc ${(q)cmd} &!"
+    local setsid=${commands[setsid]:-/usr/local/opt/util-linux/bin/setsid}
+    [[ -f $setsid ]] && setsid=${(q)setsid} || setsid=
+    cmd="$setsid zsh -dfxc ${(q)cmd} &!"
     # We use `zsh -c` instead of plain {} or () to work around bugs in zplug. It hangs on startup.
     # Double fork is to daemonize. Some macOS users had issues when gitstatusd was a child process
     # of the interactive zsh. For example, https://github.com/romkatv/powerlevel10k/issues/123