[tz] Question about bug seen in OpenBSD and FreeBSD related to tzname

Hello! Earlier this month, I noticed bugs in OpenBSD and FreeBSD related to tzname's values. https://marc.info/?l=openbsd-bugs&m=157379849727998&w=2 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241978 I noticed that both those OSes share relevant code with tzcode. How would I best test this stuff out with a recent release of tzcode? (i.e. how to make sure I'm including headers only from the 2019c tarball and not from my OS, when possible)