# Checks for header files.
AC_CHECK_HEADERS([limits.h unistd.h])
+# Checks for declarations.
+AC_CHECK_DECLS([IP_TRANSPARENT], [], [], [[
+ #include <sys/socket.h>
+ #include <linux/in.h>
+]])
+
# Checks for typedefs, structures, and compiler characteristics.
AC_HEADER_STDBOOL
AC_C_CONST