Rather than checking for <sys/sockio.h>, just include it if our other

attempts at finding SIOCATMARK have failed.  This removes one of our
Autoconf tests, which is always nice.

[originally from svn r5690]

unix/configure.ac

@@ -14,7 +14,6 @@ if test "X$GCC" = Xyes; then
     CFLAGS="$CFLAGS -Wall -Werror"
 fi
 
-AC_CHECK_HEADERS([sys/sockio.h],,,[ ])
 AC_CHECK_HEADERS([utmpx.h],,,[
 #include <sys/types.h>
 #include <utmp.h>])

unix/uxnet.c

@@ -23,7 +23,7 @@
 #include "tree234.h"
 
 /* Solaris needs <sys/sockio.h> for SIOCATMARK. */
-#ifdef HAVE_SYS_SOCKIO_H
+#ifndef SOCKATMARK
 #include <sys/sockio.h>
 #endif