The strerror_r function is the reentrant version of strerror. The
    strerror_r function uses the error number in error_code to retrieve
    the appropriate locale dependent error message. The contents of the
    error message strings are determined by the LC_MESSAGES category of
    the program's current locale.

    If error_code is EVMSERR, the function looks at vaxc$errno to get the
    OpenVMS error condition.