A user points out that the new charset-aware window title setting
doesn't work if the configured character set is one of the entries in
cp_list[] based on a hard-coded Unicode translation table, such as the
ISO 8859 family.
That's because the Windows mb_to_wc() function assumes that the code
page it's given will always be OK to pass to the Windows API function
MultiByteToWideChar, forgetting that for those internally implemented
single-byte character sets are not.
This commit adds a manual implementation of SBCS -> Unicode based on
those tables, which restores the ability to set a window title
specified in ISO 8859.
However, it's not a full fix to windows/unicode.c in general, because
wc_to_mb has a similar blind spot: it's only prepared to convert
Unicode to an internally implemented SBCS if that SBCS happens to be
the one currently set in ucsdata->line_codepage, because that's when
we've already prepared the reverse lookup table. Probably we ought to
sort that out, and arrange that it can make the reverse lookup table
if suddenly called on to do a different conversion. But that needs
more refactoring, so I haven't done it in this commit.
This is another fallback needed on Win95, where the Win32 API
functions to convert between multibyte and wide strings exist, but
they haven't heard of the UTF-8 code page. PuTTY can't really do
without that these days.
(In particular, if a server sends a remote window-title escape
sequence while the terminal is in UTF-8 mode, then _something_ needs
to translate the UTF-8 data into Unicode for Windows to reconvert into
the character set used in window titles.)
This is a weird enough thing to be doing that I've put it under the
new #ifdef LEGACY_WINDOWS, so behaviour in the standard builds should
be unchanged.
This gets rid of all those annoying 'win', 'ux' and 'gtk' prefixes
which made filenames annoying to type and to tab-complete. Also, as
with my other recent renaming sprees, I've taken the opportunity to
expand and clarify some of the names so that they're not such cryptic
abbreviations.
