Below is a patch for changing "UTC" into "UTC0" for TZ assignments.
The former is not POSIX compliant. From /usr/src/lib/libc/time/Theory:
The POSIX TZ string takes the following form:
std and dst
are 3 or more characters specifying the standard
and daylight saving time (DST) zone names.
Starting with POSIX.1-2001, std and dst may also be
in a quoted form like "<UTC+10>"; this allows
"+" and "-" in the names.
is of the form `[-]hh:[mm[:ss]]' and specifies the
[This is wrong, the colon is optional in POSIX docs]
offset west of UTC. The default DST offset is one hour
ahead of standard time.
While it makes no difference on OpenBSD, rpki-client-portable pulls from
the OpenBSD tree. There are no other portable OpenBSD subprojects that
need this change from what I could find.
Also, it might be a good idea to check for time() and setenv() errors in