date-to-time does not understand dates pre-1970

[Niklas Morberg]

In GNU Emacs 21.1.1 (i386-mingw-nt5.0.2195)
 of 2001-10-22 on PCNIKLAS2
configured using `configure --with-gcc (2.95)'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: SVE
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

date-to-time fails to recognize dates before 1970.
Evaluating the following expression with C-x C-e
will trigger the error on my platform:

(date-to-time "Jan 1 00:00:00 1969")

The resulting output from the *Backtrace* buffer is:

Debugger entered--Lisp error: (error "Invalid date: Jan 1 00:00:00 1969")
  signal(error ("Invalid date: Jan 1 00:00:00 1969"))
  error("Invalid date: %s" "Jan 1 00:00:00 1969")
  date-to-time("Jan 1 00:00:00 1969")
  eval-last-sexp-1(nil)
  eval-last-sexp(nil)
* call-interactively(eval-last-sexp)

Evaluating the same thing with a date after 1970 works, as
in the following:

(date-to-time "Jan 1 00:00:00 1970")


Recent input:
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
( d a t e - t o - t i m SPC " <backspace> <backspace> 
e SPC " C-x o C-x b C-g C-x o C-n C-n <return> <return> 
C-y C-y M-y C-p C-p C-a C-k ( d a t e - t o - t i m 
e SPC " J a n SPC 1 SPC 0 0 : 0 0 : 0 0 SPC 1 9 6 9 
" ) C-x C-e C-SPC C-n C-n C-n C-n M-w M-x r e p o r 
t <tab> <return>

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