OpenBSD perl forks for glob(). Therefore attach SIGCHLD handler as late as possible.
Commit 287a0b4 introduced a segfault when validating the i3 config as the root_screen will not be set in this case, causing a null pointer dereference. fixes #2144
287a0b4
Rename the package StartXDummy to StartXServer in the testcases library because XDummy is no longer used. No logic changes.