I'm not quite sure why I ever thought it was a good idea to have a
central variadic error() function taking an integer error code
followed by some list of arguments that depend on that code. It now
seems obvious to me that it's a much more sensible idea to have a
separate function per error, so that we can check at compile time that
the arguments to each error call are of the right number and type! So
I've done that instead.

A side effect is that the errors are no longer formatted into a
fixed-size buffer before going to stderr, so I can remove all the
%.200s precautions in the format strings.

[originally from svn r9639]

converting a number! Oops. Now you can do things like

\cfg{text-list-indent}{-2}
\cfg{text-listitem-indent}{2}

to get your bullets placed in the left margin rather than indenting
the paragraphs of your list.

[originally from svn r9474]

_output_ length, not the input length. Adjust accordingly.

This has the side effect of working around what I believe to be a
bug in DJGPP's mbstowcs(), namely that if you give it a string which
exactly fits in the output length _without_ the trailing NUL, then
it will write n-1 characters of the string plus a NUL where I
believe it should write n characters of the string and no NUL.

[originally from svn r7622]

[originally from svn r5188]

an integer charset ID.

[originally from svn r4317]

(mknew/mknewa/resize) to the PuTTY ones (snew/snewn/sresize). snewn
and mknewa have their arguments opposite ways round; this may make
the change initially painful but in the long term will free me of a
nasty context switch every time I move between codebases. Also
sresize takes an explicit type operand which is used to cast the
return value from realloc, thus enforcing that it must be correct,
and arranging that if anyone tries to compile Halibut with a C++
compiler there should be a lot less pain.

[originally from svn r4276]

end. There's a lot more _potentiality_ for new features than there
are actual new features just yet, but future highlights include:
configurable flavour of HTML (3.2, 4, XHTML Transitional or Strict),
proper character set support (this is half way there already), and
more flexible allocation of sections between multiple HTML files.
Meanwhile, immediate benefits include correct handling of special
characters within `author' and `description' strings, omission of
the filename part in hyperlinks within the same HTML file (in
particular, this means a single output file is now totally
independent of its filename), and hyperlinks to the index from the
top-level contents page (I'm amazed nobody has complained at the
lack of this yet!). There are no doubt some shiny new bugs as well,
but I'll never find them unless people start using the thing...

[originally from svn r4275]

bullet and quote characters.

[originally from svn r4249]

Newly configurable things are: bullet and quote characters as usual,
the ": " that goes between a section number and its title, the "."
coming after numbered-list item numbers, and the text "Title page"
that appears at the top of the .cnt file.

[originally from svn r4248]

and (b) it doesn't trip over strange Unicode characters in the
format string.

[originally from svn r4120]