tiny patch to fic unixware build

In the course of looking into Larry's buildfarm woes, I found that
Unixware needs this patch on HEAD to build correctly

cheers

andrew

Index: src/backend/utils/adt/timestamp.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v
retrieving revision 1.127
diff -c -r1.127 timestamp.c
*** src/backend/utils/adt/timestamp.c   29 Jun 2005 22:51:56 -0000
1.127
--- src/backend/utils/adt/timestamp.c   30 Jun 2005 03:03:42 -0000
***************
*** 19,24 ****
--- 19,25 ----
  #include <math.h>
  #include <float.h>
  #include <limits.h>
+ #include <sys/time.h>

  #include "access/hash.h"
  #include "access/xact.h"