mysqld won't give a warning any more, if --user=user_name is used,

if 'user_name' is the current user and it is not root.

sql/mysqld.cc

@@ -1014,13 +1014,20 @@ static void set_user(const char *user)
 {
 #if !defined(__WIN__) && !defined(OS2) && !defined(__NETWARE__)
   struct passwd *ent;
+  uid_t user_id= geteuid();
 
   // don't bother if we aren't superuser
-  if (geteuid())
+  if (user_id)
   {
     if (user)
+    {
+      /* Don't give a warning, if real user is same as given with --user */
+      struct passwd *user_info= getpwnam(user);
+
+      if (!user_info || user_id != user_info->pw_uid)
 	fprintf(stderr,
 		"Warning: One can only use the --user switch if running as root\n");
+    }
     return;
   }
   else if (!user)