readline and openbsd

I noticed a change in src/bin/psql/input.h dated 3 weeks ago.

It did not fix the problem that psql builds without command history
support on OpenBSD. Problem is that OpenBSD has history support but no
history.h file. Here's a patch:

*** bin/psql/input.h.orig    Wed Apr 12 12:16:22 2000
--- bin/psql/input.h    Wed Oct 25 13:25:44 2000
***************
*** 25,36 ****
  #endif

  #if defined(HAVE_LIBHISTORY) || (defined(HAVE_LIBREADLINE) && defined(HAVE_HISTORY_IN_READLINE))
  #if defined(HAVE_READLINE_HISTORY_H)
  #include <readline/history.h>
- #define USE_HISTORY 1
  #elif defined(HAVE_HISTORY_H)
  #include <history.h>
- #define USE_HISTORY 1
  #endif
  #endif

--- 25,35 ----
  #endif

  #if defined(HAVE_LIBHISTORY) || (defined(HAVE_LIBREADLINE) && defined(HAVE_HISTORY_IN_READLINE))
+ #define USE_HISTORY 1
  #if defined(HAVE_READLINE_HISTORY_H)
  #include <readline/history.h>
  #elif defined(HAVE_HISTORY_H)
  #include <history.h>
  #endif
  #endif