Rather than make this a Linux test, we should just test for the existence

of endian.h.  I figure that if it exists it's pretty sure that it has
the byte order information and we may catch some other ports without
any further testing.

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

src/backend/libpq/pqcomprim.c

@@ -1,6 +1,10 @@
 #include <stdlib.h>
 #include <stdio.h>
 
+#ifdef        HAVE_ENDIAN_H
+#  include    <endian.h>
+#endif
+
 #include "postgres.h"
 #include "libpq/pqcomm.h"
 

src/configure.in

@@ -134,7 +134,7 @@ dnl Checks for header files.
 AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS(limits.h unistd.h termios.h values.h sys/select.h)
-AC_CHECK_HEADERS(readline.h history.h dld.h crypt.h)
+AC_CHECK_HEADERS(readline.h history.h dld.h crypt.h endian.h)
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST

src/include/config.h.in

@@ -14,6 +14,9 @@
  * The following is set using configure.  
  */
 
+/* Set to 1 if you have <endian.h> */
+#undef HAVE_ENDIAN_H
+
 /* Set to 1 if you have <crypt.h> */
 #undef HAVE_CRYPT_H