+ AC_COMPILE_IFELSE(
+ [AC_LANG_SOURCE([[
+#include <time.h> /* for time_t */
+#include <limits.h> /* for CHAR_BIT, LONG_MIN, LONG_MAX */
+#define TYPE_MINIMUM(t) \
+ ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+#define TYPE_MAXIMUM(t) \
+ ((t) ((t) 0 < (t) -1 ? (t) -1 : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
+typedef int verify_min[2 * (LONG_MIN <= TYPE_MINIMUM (time_t)) - 1];
+typedef int verify_max[2 * (TYPE_MAXIMUM (time_t) <= LONG_MAX) - 1];
+ ]])],
+ [AC_DEFINE([TIME_T_FITS_IN_LONG_INT], [1],
+ [Define to 1 if all 'time_t' values fit in a 'long int'.])
+ ])