Added shutdown macros for win32 required for QUIC.

src/os/win32/ngx_socket.h

@@ -14,6 +14,8 @@
 
 
 #define NGX_WRITE_SHUTDOWN SD_SEND
+#define NGX_READ_SHUTDOWN  SD_RECEIVE
+#define NGX_RDWR_SHUTDOWN  SD_BOTH
 
 
 typedef SOCKET  ngx_socket_t;