[Discuss-gnuradio] Heads up: Changing of the gr::trellis::interleaver's random interleaver

[CEL]

Hi collection of information theorists with the highest entropy known
to SDRkind,

just a warning: I'm opening a PR that'll change the random generation
for the random interleaver. That means you can't decode data encoded
with the old code using the new code.

The reason is simple: the old code used the non-threadsafe and overall
terrible libc `rand()`. Terribleness isn't a blocker per se, but the
lack of thread can lead to very serious problems, so we had to replace
that with our xoroshiro128+ implementation (which, bonus, is faster, at
least on my system).

If you have an application that actually needs to exchange old-style
random interleaved data with GNU Radio 3.8 (which is the release where
this change will take effect), please comment under the pull request or
here or directly and confidentially to me.

Best regards,
Marcus