diff --git a/configure.in b/configure.in
index 412d4584..03556fe7 100644
--- a/configure.in
+++ b/configure.in
@@ -150,6 +150,7 @@ dnl * accept header files where to find the typedef..
 AC_MSG_CHECKING([for socklen_t])
 AC_CACHE_VAL(irssi_cv_type_socklen_t,
 [AC_TRY_COMPILE([
+#include <sys/types.h>
 #include <sys/socket.h>],
 [socklen_t t;],
 irssi_cv_type_socklen_t=yes,