If wcwidth() isn't available (Windows), previously it was assumed
that one byte == one column in the terminal. Now it is assumed that
one multibyte character == one column. This works better with UTF-8.
Languages that only use single-width characters without any combining
characters should work correctly with this.
In xz, none of po/*.po contain combining characters and only ko.po,
zh_CN.po, and zh_TW.po contain fullwidth characters. Thus, "only"
those three translations in xz are broken on Windows with the
UTF-8 code page. Broken means that column headings in xz -lvv and
(only in the master branch) strings in --long-help are misaligned,
so it's not a huge problem. I don't know if those three languages
displayed perfectly before the UTF-8 change because I hadn't tested
translations with native Windows builds before.
Fixes: 46ee0061629fb075d61d83839e14dd193337af59
The code assumed that printing numbers with thousand separators
and decimal points would always produce only US-ASCII characters.
This was used for buffer sizes (with snprintf(), no overflows)
and aligning columns of the progress indicator and --list. That
assumption was wrong (e.g. LC_ALL=fi_FI.UTF-8 with glibc), so
multibyte character support was added in this commit. The old
way is used if the operating system doesn't have enough multibyte
support (e.g. lacks wcwidth()).
The sizes of buffers were increased to accomodate multibyte
characters. I don't know how big they should be exactly, but
they aren't used for anything critical, so it's not too bad.
If they still aren't big enough, I hopefully get a bug report.
snprintf() takes care of avoiding buffer overflows.
Some static buffers were replaced with buffers allocated on
stack. double_to_str() was removed. uint64_to_str() and
uint64_to_nicestr() now share the static buffer and test
for thousand separator support.
Integrity check names "None" and "Unknown-N" (2 <= N <= 15)
were marked to be translated. I had forgot these, plus they
wouldn't have worked correctly anyway before this commit,
because printing tables with multibyte strings didn't work.
Thanks to Marek Černocký for reporting the bug about
misaligned table columns in --list output.
