On some systems limits.h is needed to define DBL_MIN.

From: "D'Arcy J.M. Cain" <darcy@druid.net>

src/backend/utils/adt/dt.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/dt.c,v 1.10 1997/03/25 20:02:42 scrappy Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/dt.c,v 1.11 1997/03/28 06:53:50 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -23,6 +23,9 @@
 #ifdef HAVE_FLOAT_H
 # include <float.h>
 #endif
+#ifdef HAVE_LIMITS_H
+# include <limits.h>
+#endif
 #ifndef USE_POSIX_TIME
 #include <sys/timeb.h>
 #endif