ESP8266's settimeofday() returns EINVAL (22) directly as the return
value when the timezone parameter is non-NULL, rather than following
POSIX convention of returning -1 and setting errno. The previous
fallback code checked errno == EINVAL which never matched because
errno was never set, so the retry with nullptr never triggered.
Fix by always passing nullptr on ESP8266 since the platform requires it.
J. Nick Koston
d6db522b1d