Coding systems vietnamese-vscii and vietnamese-tcvn

[Ulrich Mueller]

language/vietnamese.el defines coding systems vietnamese-vscii
(with charset vscii) and vietnamese-tcvn (with charset tcvn-5712).
However, mule-conf.el defines the two charsets as aliases [1]:

   (define-charset-alias 'tcvn-5712 'vscii)

Indeed, a file containing bytes 0x00 to 0xff decodes to the same buffer
contents, regardless if its coding is specified as vscii or as tcvn.

Wikipedia also seems to say that these are only different names for
the same encoding: https://en.wikipedia.org/wiki/VSCII

Should coding system vietnamese-tcvn be an alias for vietnamese-vscii
(or the other way around)?


[1] I tried to trace the history of this definition, but I gave up at
merge(?) commit 8f924df7df01, neither of whose parents have the line.
Apparently conversion from CVS isn't perfect.