-#define EADDRINUSE WSAEADDRINUSE
-#define EWOULDBLOCK WSAEWOULDBLOCK
-#define EINPROGRESS WSAEINPROGRESS
-#define EALREADY WSAEALREADY
-#define EISCONN WSAEISCONN
-#define ENOTCONN WSAENOTCONN
-#define ENOBUFS WSAENOBUFS
-#define SHUT_RDWR SD_BOTH
+#ifndef EADDRINUSE
+# define EADDRINUSE WSAEADDRINUSE
+#endif
+
+#ifndef EWOULDBLOCK
+# define EWOULDBLOCK WSAEWOULDBLOCK
+#endif
+
+#ifndef EINPROGRESS
+# define EINPROGRESS WSAEINPROGRESS
+#endif
+
+#ifndef EALREADY
+# define EALREADY WSAEALREADY
+#endif
+
+#ifndef EISCONN
+# define EISCONN WSAEISCONN
+#endif
+
+#ifndef ENOTCONN
+# define ENOTCONN WSAENOTCONN
+#endif
+
+#ifndef ENOBUFS
+# define ENOBUFS WSAENOBUFS
+#endif
+
+#ifndef SHUT_RDWR
+# define SHUT_RDWR SD_BOTH
+#endif