Add darwin platform encodings, esp. UTF8

Copied from freebsd, fixes t/spec/S05-mass/charsets.rakudo.parrot
./perl6-p -e'my $latin-chars = [~] chr(0)..chr(0xFF);
  my $test = "abcdefghijklmnopqrstuvwxyzµßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ";
  say $latin-chars.comb(/<lower>/).join, $test'
See [GH #1092]
[cage] fix copyright formats in 2 new files, tune changelog