Revert "Add socket wrapper"

This reverts commit 85e745121f.

src/tls13.c

@@ -13,6 +13,15 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <unistd.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#endif
 #include <gmssl/rand.h>
 #include <gmssl/x509.h>
 #include <gmssl/error.h>