Bug#53908: compile failure with embedded enabled

This fixes a recently introduced regression, where a variable is
not defined for the embedded server. Although the embedded server
is not supported in 5.0, make it at least compile.

sql/sql_parse.cc

@@ -493,6 +493,7 @@ int check_user(THD *thd, enum enum_server_command command,
       }
       send_ok(thd);
       thd->password= test(passwd_len);          // remember for error messages 
+#ifndef EMBEDDED_LIBRARY
       /*
         Allow the network layer to skip big packets. Although a malicious
         authenticated session might use this to trick the server to read
@@ -500,6 +501,7 @@ int check_user(THD *thd, enum enum_server_command command,
         that needs to be preserved as to not break backwards compatibility.
       */
       thd->net.skip_big_packet= TRUE;
+#endif
       /* Ready to handle queries */
       DBUG_RETURN(0);
     }