There was a stale 'doc/texinfo.tex' here (no idea where it's from).
After removing it, everything works out smooth. Sorry for the wind.

Regards, Tim

On 10/18/19 10:02 AM, Tim Rühsen wrote:
> @Paul
> 
> The error says
> "/home/oms/src/libmicrohttpd/doc/gpl-2.0.texi:286: This command can
> appear only outside of any environment, not in environment @enumerate."
> 
> 
> Line 286 is
> @heading NO WARRANTY
> 
> $ grep -n enumerate gpl-2.0.texi
> 67:@enumerate 0
> 104:@enumerate a
> 126:@end enumerate
> 153:@enumerate a
> 173:@end enumerate
> 314:@end enumerate
> 
> As you can see L67-L314 is an enumerate, where L286 (@heading) is enclosed.
> 
> So it looks like a problem in gpl-2.0.texi (or in the texi2dvi command
> chain). Any ideas ?
> 
> Regards, Tim
> 
> 
> On 10/18/19 9:54 AM, Tim Rühsen wrote:
>> Hi Christian,
>>
>> I can even reproduce on Debian unstable:
>>
>> ./bootstrap
>> ./configure
>> make
>> cd doc
>> make dvi
>>
>> Regards, Tim
>>
>> On 10/17/19 3:11 PM, Christian Grothoff wrote:
>>> I downloaded an Ubuntu 18.04.3 LTS VM image, installed the required
>>> packages (including texlive 2017 and texinfo 6.5) and it _still_ works
>>> for me. I did try the texi2dvi command and others.
>>>
>>> Tim: So sorry, but I cannot reproduce the problem.
>>>
>>> Paul: I also completely fail to comprehend the error message and how it
>>> would point to an issue in libmicrohttpd.texi. But if it doesn't reflect
>>> an issue in gpl-2.0.texi, I guess you're off the hook ;-).
>>>
>>> Happy hacking!
>>>
>>> Christian
>>>
>>> On 10/13/19 9:14 PM, Paul Eggert wrote:
>>>> On 10/13/19 9:01 AM, Christian Grothoff wrote:
>>>>> I suspect what you discovered could be a bug in gnulib when
>>>>> the license file is used against some particular (maybe very recent)
>>>>> texinfo installation/version.
>>>>
>>>> I see the problem on Ubuntu 18.04.3 LTS which has GNU texinfo 6.5 and
>>>> TeX Live 2017/Debian. It's due to a bug in libmicrohttpd.texi that is
>>>> unrelated to Gnulib's gpl-2.0.texi. If I install the attached patch,
>>>> "make dvi" outputs the following diagnostics. I suggest getting an
>>>> appropriate texinfo and TeX Live to debug this.
>>>>
>>>> make[2]: Entering directory '/home/eggert/junk/d/libmicrohttpd/doc'
>>>> TEXINPUTS="../build-aux:$TEXINPUTS" \
>>>> MAKEINFO='/bin/bash /home/eggert/junk/d/libmicrohttpd/build-aux/missing
>>>> makeinfo   -I .' \
>>>> texi2dvi  --build-dir=libmicrohttpd.t2d -o libmicrohttpd.dvi  \
>>>> libmicrohttpd.texi
>>>> This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017/Debian)
>>>> (preloaded format=etex)
>>>>  restricted \write18 enabled.
>>>> entering extended mode
>>>> (../../../.././libmicrohttpd.texi
>>>> (/home/eggert/junk/d/libmicrohttpd/build-aux/texinfo.tex
>>>> Loading texinfo [version 2013-02-01.11]: pdf, fonts, markup, glyphs,
>>>> page headings, tables, conditionals, indexing, sectioning, toc,
>>>> environments,
>>>> defuns, macros, cross references, insertions,
>>>> (/usr/share/texlive/texmf-dist/tex/generic/epsf/epsf.tex
>>>> This is `epsf.tex' v2.7.4 <14 February 2011>
>>>> ) localization, formatting, and turning on texinfo input format.)
>>>> (./libmicrohttpd.aux)
>>>> Runaway argument?
>>>> {microhttpd-optio
>>>> ../../../.././libmicrohttpd.texi:2: File ended while scanning use of
>>>> @xrdef.
>>>> <inserted text>
>>>>                 @par
>>>> @readdatafile ...etupdatafile @input @jobname .#1
>>>>                                                   @endgroup
>>>> @tryauxfile ... @ifeof 1 @else @readdatafile {aux}
>>>>                                                   @global @havexrefstrue
>>>> @fi...
>>>>
>>>> @setfilename ->@fixbackslash @iflinks @tryauxfile
>>>>                                                   @immediate @openout
>>>> @auxfi...
>>>> l.2 @setfilename
>>>>                  libmicrohttpd.info
>>>> ?
>>>
>>
>