When stdoff is used for judgment, the value of stdoff is incorrect when it is
switched from the rearguard mode to the vanguard mode. The value should be
1:00, but the actual value is 0:00.
Test steps:
1. make VERSION=2026b ZFLAGS="-b fat" tzdata2026b-rearguard.tar.gz.t
2. tar xvf tzdata2026b-rearguard.tar.gz
3. make DATAFORM=vanguard all
vanguard.zi:
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone Africa/Casablanca -0:30:20 - LMT 1913 Oct 26
0:00 Morocco %z 1984 Mar 16
1:00 - %z 1986
0:00 Morocco %z 2018 Oct 28 3:00
0:00 Morocco %z 2026 Sep 20 2:00
0:00 - %z
