'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"';
}
+ if ($args{xtrace}) {
+ my $out = "$outdir/xtrace-for-$test.log";
+
+ # See comment in $args{strace} branch.
+ $cmd = qq|xtrace -n -o "$out" -- | .
+ 'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"';
+ }
+
# We need to use the shell due to using output redirections.
exec '/bin/sh', '-c', $cmd;