--- a/tools/inetcat.c
+++ b/tools/inetcat.c
@@ -33,6 +33,7 @@
 #include <windows.h>
 #include <winsock2.h>
 #else
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <sys/ioctl.h>
