[tz] strftime and nonnormalized dates/times

[Paul Eggert]

Steve Summit wrote:
> When calling strftime, are tm_hour, tm_min, and the rest
> limited to their normal ranges, or not?

Although they aren't limited, you can't rely on what strftime outputs from 
out-of-range values. The C11 standard and POSIX-2018 both say, "If any of the 
specified values is outside the normal range, the characters stored are 
unspecified."