makeinfo 4.13 support?

[Peter Simons]

Hi,

the autoconf-archive project uses the "gendocs" module to convert its
Texinfo documentation into HTML, and this used to work just fine. In
recent versions like v0.1-788-g190bc0f, however, calls to "makeinfo"
fail with the following error message:

 | Generating monolithic html... (env LANG= LC_MESSAGES= LC_ALL= LANGUAGE= 
makeinfo --no-split --html -o autoconf-archive.html    
--css-ref=/software/gnulib/manual.css -c TOP_NODE_UP_URL=/manual 
"/home/simons/build/autoconf-archive/doc/autoconf-archive.texi")
 | makeinfo: invalid option -- 'c'
 | Try `makeinfo --help' for more information.

I reckon that is because those builds run on Ubuntu Precise, which has
only makeinfo version 4.13 available and which doesn't support the
"--css-ref" flag.

So I was wondering whether there is any way to remedy this issue? Would
it be possible for gnulib to detect the presence of the old version and
to omit the flag in that case?

Best regards,
Peter