Fix testsuite on OpenBSD

OpenBSD perl forks for glob().
Therefore attach SIGCHLD handler as late as possible.

testcases/lib/StartXServer.pm

@@ -69,15 +69,6 @@ sub start_xserver {
     my @displays = ();
     my @childpids = ();
 
-    $SIG{CHLD} = sub {
-        my $child = waitpid -1, POSIX::WNOHANG;
-        @pids = grep { $_ != $child } @pids;
-        return unless @pids == 0;
-        print STDERR "All X server processes died.\n";
-        print STDERR "Use ./complete-run.pl --parallel 1 --keep-xserver-output\n";
-        exit 1;
-    };
-
     # Yeah, I know it’s non-standard, but Perl’s POSIX module doesn’t have
     # _SC_NPROCESSORS_CONF.
     my $num_cores;
@@ -101,6 +92,15 @@ sub start_xserver {
 
     say "Starting $parallel Xephyr instances, starting at :$displaynum...";
 
+    $SIG{CHLD} = sub {
+        my $child = waitpid -1, POSIX::WNOHANG;
+        @pids = grep { $_ != $child } @pids;
+        return unless @pids == 0;
+        print STDERR "All X server processes died.\n";
+        print STDERR "Use ./complete-run.pl --parallel 1 --keep-xserver-output\n";
+        exit 1;
+    };
+
     my @sockets_waiting;
     for (1 .. $parallel) {
         my $socket = fork_xserver($keep_xserver_output, $displaynum,

testcases/t/180-fd-leaks.t

@@ -20,6 +20,9 @@ use i3test;
 use POSIX qw(mkfifo);
 use File::Temp qw(:POSIX tempfile);
 
+SKIP: {
+skip "Procfs not available on $^O", 1 if $^O eq 'openbsd';
+
 my $i3 = i3(get_socket_path());
 
 my $tmp = tmpnam();
@@ -59,4 +62,6 @@ for my $fd (keys %fds) {
 
 is(scalar keys %fds, 0, 'No file descriptors leaked');
 
+}
+
 done_testing;