Unix sockets on BeOS

BeOS doesn't have Unix sockets, so alter config.h.in to set the
define correctly.

Index: src/include/config.h.in
==================================================================RCS
file: /home/projects/pgsql/cvsroot/pgsql/src/include/config.h.in,v
retrieving revision 1.140
diff -u -u -r1.140 config.h.in
--- src/include/config.h.in     2000/10/03 19:50:21     1.140
+++ src/include/config.h.in     2000/10/07 12:51:45
@@ -227,7 +227,7 @@
  * Define this is your operating system kernel supports AF_UNIX family
  * sockets.
  */
-#if !defined(__CYGWIN__) && !defined(__QNX__)
+#if !defined(__CYGWIN__) && !defined(__QNX__) && !defined(__BEOS__)
 # define HAVE_UNIX_SOCKETS 1
 #endif