Generating charset map files during bootstrap

[Glenn Morris <rgm@gnu.org>]

I'm interested in removing (at least some of) the etc/charset/*.map
files from the repository, and generating them during bootstrap (the
first time only, as is done eg for the unidata files). To that end:

1) Please could Someone(s) check that this works on MS Windows:

cd admin/charsets
make extraclean
make local

Ie, regenerates files in etc/charsets.
If it doesn't, please figure out what needs fixing, TIA very much. ;)

Note that the following charsets are regenerated with slight differences:
CNS-6.map, GB180302.map, GB180304.map

This is true in emacs-24 as well. I have no idea what the differences mean,
expect that presumably these files are out-of-sync with their sources?


2) We don't keep all the sources for the charset mapfiles in Emacs.
(Isn't this the kind of thing we have gotten in trouble for before?)
Some are in admin/charsets/mapfiles, but the rest are taken from
/usr/share/i18n/charmaps. Adding the relevant files to the Emacs repo
would add 103 (compressed) files to admin/charsets, totalling 2.2MB in
size (which is 10% less than the existing mapfiles/ directory). 2/103
account for 1MB of the size.

Shouldn't those sources be added?

Then all etc/charsets/*.map files could be removed (131 files, 3.1MB).
So a net win for a git snapshot (a loss for tarballs, which would
have both versions).