ANSI C.

[VLD/VMB]

As an X3J11 C implementor, it would be your job to
arrange for the correct operation of routines such
as gmtime().  This CAN be done on any non-UNIX system.
2.nBSD (for n around 3) even implemented per-user
environments without kernel support.

For example (not necessarily optimum), DST could be
indicated by the presence of a specific system file.
The implementation of gmtime() would test for this
(the first time it is called within the process).

I think the concept of DST is stupid, but so long as
it has to be dealt with, some means must be provided.