time: Set daylight to 1 for matching DST/offset change (bug 29951)

The daylight variable is supposed to be set to 1 if DST is ever in
use for the current time zone.  But __tzfile_read used to do this:

  __daylight = rule_stdoff != rule_dstoff;

This check can fail to set __daylight to 1 if the DST and non-DST
offsets happen to be the same.

1 files changed, 0 insertions, 0 deletions

diff --git a/timezone/testdata/XT6 b/timezone/testdata/XT6
new file mode 100644
index 0000000..07b393b
--- /dev/null
+++ b/timezone/testdata/XT6