Show deprecation warning on Socket.gethostbyname and Socket.gethostbyaddr

ext/socket/socket.c

@@ -965,6 +965,7 @@ sock_sockaddr(struct sockaddr *addr, socklen_t len)
 static VALUE
 sock_s_gethostbyname(VALUE obj, VALUE host)
 {
+    rb_warn("Socket.gethostbyname is deprecated; use Addrinfo.getaddrinfo instead.");
     struct rb_addrinfo *res =
 	rsock_addrinfo(host, Qnil, AF_UNSPEC, SOCK_STREAM, AI_CANONNAME);
     return rsock_make_hostent(host, res, sock_sockaddr);
@@ -1004,6 +1005,8 @@ sock_s_gethostbyaddr(int argc, VALUE *argv, VALUE _)
     VALUE ary, names;
     int t = AF_INET;
 
+    rb_warn("Socket.gethostbyaddr is deprecated; use Addrinfo#getnameinfo instead.");
+
     rb_scan_args(argc, argv, "11", &addr, &family);
     StringValue(addr);
     if (!NIL_P(family)) {