do not include a header in cygwin #341

examples/networklayer_tcp.c

@@ -18,7 +18,9 @@
 # include <fcntl.h>
 # include <sys/select.h>
 # include <netinet/in.h>
-# include <netinet/tcp.h>
+#ifndef __CYGWIN__
+    # include <netinet/tcp.h>
+#endif
 # include <sys/ioctl.h>
 # include <netdb.h> //gethostbyname for the client
 # include <unistd.h> // read, write, close