enable other modes of use like the built-in --cgi mode, without
me having to anticipate them in detail.)
+ - non-ASCII character set support
+ + could usefully apply to --title and also to file names
+ + how do we determine the input charset? Via locale, presumably.
+ + how do we do translation? Importing my charset library is one
+ heavyweight option; alternatively, does the native C locale
+ mechanism provide enough functionality to do the job by itself?
+ + in HTML, we would need to decide on an _output_ character set,
+ specify it in a <meta http-equiv> tag, and translate to it from
+ the input locale
+ - one option is to make the output charset the same as the
+ input one, in which case all we need is to identify its name
+ for the <meta> tag
+ - the other option is to make the output charset UTF-8 always
+ and translate to that from everything else
+ - in the web server and CGI modes, it would probably be nicer
+ to move that <meta> tag into a proper HTTP header
+ + even in text mode we would want to parse the filenames in some
+ fashion, due to the unhelpful corner case of Shift-JIS Windows
+ (in which backslashes in the input string must be classified as
+ path separators or the second byte of a two-byte character)
+ - that's really painful, since it will impact string processing
+ of filenames throughout the code
+ - so perhaps a better approach would be to do locale processing
+ of filenames at _scan_ time, and normalise to UTF-8 in both
+ the index and dump files?
+ + involves incrementing the version of the dump-file format
+ + then paths given on the command line are translated
+ quickly to UTF-8 before comparing them against index paths
+ + and now the HTML output side becomes easy, though the text
+ output involves translating back again
+ + but what if the filenames aren't intended to be
+ interpreted in any particular character set (old-style
+ Unix semantics) or in a consistent one?
+
- we could still be using more of the information coming from
autoconf. Our config.h is defining a whole bunch of HAVE_FOOs for
particular functions (e.g. HAVE_INET_NTOA, HAVE_MEMCHR,