Really make sctp_assoc_value test work correctly, at least on FreeBSD.

configure.ac

@@ -88,8 +88,9 @@ AC_C_CONST
 AC_CHECK_HEADERS([sys/socket.h])
 AC_CHECK_HEADERS([netinet/sctp.h],
 		 AC_DEFINE([HAVE_SCTP], [1], [Have SCTP support.])
-		 AC_SEARCH_LIBS(sctp_bindx, [sctp]),
-		 AC_CHECK_TYPES([struct sctp_assoc_value])
+		 AC_SEARCH_LIBS(sctp_bindx, [sctp])
+		 AC_CHECK_TYPES([struct sctp_assoc_value], [], [],
+				[[#include <netinet/sctp.h>]]),
 		 [],
 		 [#ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>