Returning small structs by value

[Jose E. Marchesi]

Hello people.

Luckily (we were not put in CC) pinskia noticed the LLVM pull request

  https://github.com/llvm/llvm-project/pull/206876

which changes the BPF ABI by returning small structs via registers,
following similar (the same?) rules than the passing of small structs
they implemented some time ago.

So I have created a bugzilla, resulting in:

  bug 107438 bpf: support passing small record arguments by value
  bug 126061 bpf: support returning small record arguments by value

I have also updated the wiki.

Salud!