+Format, +StampOrDateTime, +Locale)Format time given a specified Locale. This predicate is a
work-around for lacking proper portable and thread-safe time and locale
handling in current C libraries. In its current implementation the only
value allowed for Locale is
currently only modifies the behaviour of the
B format specifiers. The predicate is used to be able
to emit POSIX locale week and month names for emitting standardised
time-stamps such as RFC1123.