>>> any why [symbol renaming] is used in NetBSD?
>> For backwards compatibility.
> Do you mean that ALL/MOST programs/packages built for older NetBSD
> releases should work without recompilation with newer NetBSD versions
> and NetBSD releases are ALWAYS binary backward compatible with older
> releases?

ALWAYS?  No.  But almost - at least if the kernel in use was built with
the relevant COMPAT_* options enabled.

> Or at least there is such goal?

Yes.

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