A message “ ‘sys_errlist’ is deprecated; use ‘strerror’ or ‘strerror_r’ instead ”

Q: While building nginx version 0.7.66, 0.8.35 or higher on Linux the following warning messages are issued:

warning: `sys_errlist' is deprecated;
    use `strerror' or `strerror_r' instead
warning: `sys_nerr' is deprecated;
    use `strerror' or `strerror_r' instead

A: This is normal: nginx has to use the deprecated sys_errlist[] and sys_nerr in signal handlers because strerror() and strerror_r() functions are not Async-Signal-Safe.