slib2c0: time killer

[Aubrey Jaffer <jaffer@martigny.ai.mit.edu>]

I released slib2c0 today.  In slib2c0, I completed implementing the
POSIX time functions.  SLIB's implementation should be less troublesome
than depending on C-libraries.  Here are comments from "timezone.scm":

 The C-library support for time in general and time-zones in particular
 stands as a fine example of how *not* to create interfaces.
 
 Functions are not consistently named.  Support for GMT is offered in one
 direction only; The localtime function returns some timezone data in the
 structure which it returns, and some data in shared global variables.
 The structure which localtime returns is overwritten with each
 invocation.  There is no way to find local time in zones other than GMT
 and the local timezone.
 
 The tzfile(5) format encodes only a single timezone per file.  There is
 no dispatch on zone names, so multiple copies of a timezone file exist
 under different names.  The TZ `:' specification is unix filesystem
 specific.  The tzfile(5) format makes no provision for byte-order
 differences; It mixes 32-bit integer data with characters; specifying
 ASCII bytes, it is incompatible with different character sizes.  The
 binary format makes it impossible to easily inspect a file for
 corruption.
 
 I have corrected most of the failings of the C-library time interface in
 SLIB while maintaining compatablility.  I wrote support for Linux
 timezone files because on a system where TZ is not set, there is no
 other way to reveal this information.  HP-UX appears to have a more
 sensible arrangement; I invite you to add support for it and other
 platforms.
 
 Writing this was a long, tedious, and unenlightening process.  I hope it
 is useful.

 Sat Nov 15 00:15:33 1997  Aubrey Jaffer  <jaffer@martigny.ai.mit.edu>