Fix local time when TZ is not set

[balki]

sec2localtime is returning UTC time unless TZ was explicitly set either via environment variable TZ or --tz cli fag. Golang sets time.Local correctly even without TZ. But it is overridden at SetTZFromEnv. When TZ is unset (i.e. ""), LoadLocation returns UTC doc.

If the name is "" or "UTC", LoadLocation returns UTC. If the name is "Local", LoadLocation returns Local.

---

❯ date
Tue 17 Sep 2024 10:41:02 AM EDT

❯ printf '{"ts": %s }' $(date +"%s") | go run cmd/mlr/main.go --jsonl put '$ts = sec2localtime($ts)'
{"ts": "2024-09-17 10:41:06"}

❯ printf '{"ts": %s }' $(date +"%s") | mlr --jsonl put '$ts = sec2localtime($ts)'
{"ts": "2024-09-17 14:41:09"}

❯ mlr --version
mlr 6.12.0

❯ env | grep TZ

❯ env | grep TZ || echo "not found"
not found

[johnkerl]

Thank you @balki !! :)