With Perl 5 embedding, the full Unicode range is supported via
charnames.pm. Without Perl 5 embedding (e.g. in "make ghci"),
only codepoints in the range 0x00-0xFF are supported.
Note: Now Perl5 embedding is on by default, we can implement
more "core" Pugs functionalities this way, instead of maintaining
huge amount of duplicate information. (Encode.pm comes to mind.)