--- nmap-6.01.org/nbase/nbase.h
+++ nmap-6.01/nbase/nbase.h
@@ -126,7 +126,7 @@
  *
  * * Various Windows -> UNIX compatability definitions are added (such as defining EMSGSIZE to WSAEMSGSIZE)
  */
-
+#include <sys/select.h>
 #if HAVE_CONFIG_H
 #include "nbase_config.h"
 #else