Also enable translation of PG_WIN874, which certainly seems to have an
obvious translation now, though maybe it did not at the time this table's
ancestor was created.
since this will allow initdb to reject attempts to initdb in a locale
that uses such an encoding. We'll probably find out more such names
during beta ...
databases with encodings that are incompatible with the server's LC_CTYPE
locale, when we can determine that (which we can on most modern platforms,
I believe). C/POSIX locale is compatible with all encodings, of course,
so there is still some usefulness to CREATE DATABASE's ENCODING option,
but this will insulate us against all sorts of recurring complaints
caused by mismatched settings.
I moved initdb's existing LC_CTYPE-to-encoding mapping knowledge into
a new src/port/ file so it could be shared by CREATE DATABASE.