This is a major change of how the filters are interpreted. If everything
works how it should, it should not affect you unless you are hacking the
filters themselves.
Anyway, this change should make a huge improvement in the filter performance
as previous benchmarks showed that our major problem lies in the
recursion itself.
There are also some changes in nest and protocols, related mostly to
spreading const declarations throughout the whole BIRD and also to
refactored dynamic attribute definitions. The need of these came up
during the whole work and it is too difficult to split out these
not-so-related changes.
With 32 bits, size of the args is 12 bytes, the f_val is 20 bytes.
With 64 bits, size of the args is 24 bytes, the f_val the same.
This is not so nice on 32 bits, anyway the f_inst itself is
24 vs. 32 bytes and the overall size of filters must be 32k of
instructions to get to one megabyte of RAM eaten by f_inst.
Therefore it seems to be improbable for common user to get into
problems with this change.
