// If error>=0 then the result is to do strerror_r(error, buf, buflen), that is fill buf with a descriptive error message.
// If error>=0 then the result is to do strerror_r(error, buf, buflen), that is fill buf with a descriptive error message.
// If error<0 then return a TokuDB-specific error code. For unknown cases, we return -1 and set errno=EINVAL, even for cases that *should* be known. (Not all DB errors are known by this function which is a bug.)
// If error<0 then return a TokuDB-specific error code. For unknown cases, we return -1 and set errno=EINVAL, even for cases that *should* be known. (Not all DB errors are known by this function which is a bug.)