Bug#177940: AC_FUNC_MKTIME fail when timezone is set to GMT-2

[Lars Wirzenius <liw@iki.fi>]

tag 177940 + fixed-in-experimental
thanks

I used the attached program (based on the test in autoconf) to test that
this bug occurs with libc6 2.3.2.ds1-22 (the version in unstable) but
not with version 2.5.2-2 (the version in experimental). Thus, I tag it
fixed-in-experimental.

#include <time.h>
#include <stdio.h>

#define time_t_max ((time_t) ~0UL)

static int
mktime_test (time_t now)
{
  struct tm *lt;
  if ((lt = localtime (&now)) && mktime (lt) != now)
    return 2;
  now = time_t_max - now;
  if ((lt = localtime (&now)) && mktime (lt) != now)
    return 3;
  return 0;
}

int main(void)
{
  int ret;

  ret = mktime_test(time(NULL));
  printf("mktime_test: %d\n", ret);
  return ret;
}