bug#81424: 32.0.50; Build time dependency on TeX

Ping!  Can we please make some progress in this issue?  Or maybe we
should close it?

> Cc: "[email protected]" <[email protected]>
> From: Vincent Belaïche <[email protected]>
> Date: Fri, 17 Jul 2026 12:15:40 +0000
> 
> Dear Ulrich,
> 
> > texinfo.tex is in Emacs' doc/misc/ directory.
> 
> I am quite surprised by this, and this could break some compilation, probably we should just evolve Makefile.in
> files to remove targets needing tex/texindex when these tools are not installed or not working. But this is
> another issue.
> 
> > TeX is not what most people would call a system package. [...]
> 
> I fully agree with you that Emacs build should not need tex/texindex installed. You have spotted a problem:
> thank you for reporting this. I was just arguing about calling tex "not standard", this is anyway subjective, as I am
> a contributer to LaTeX/Texinfo etc. so to me they are quite standard, but you had in mind some OS system
> packages. So we were just comparing apples to carrots.
> 
> Now, I have pushed a branch scratch/remove-build-tex-prerequisite with a fix for the problem you have
> reported. Please let me know if it solves it and when other Emacs experts confirm that it is ok for them too I will
> cherry pick it to master.
> 
>    Vincent.
> ------------------------------------------------------------------------------
> De : Ulrich Müller <[email protected]>
> Envoyé : jeudi 16 juillet 2026 13:36
> À : Vincent Belaïche <[email protected]>
> Cc : [email protected] <[email protected]>; [email protected] <[email protected]>
> Objet : Re: 32.0.50; Build time dependency on TeX 
>  
> >>>>> On Thu, 16 Jul 2026, Vincent Belaïche wrote:
> 
> > To my knowledge texinfo.tex is not bundled with Emacs but is install
> > separately as part of a TeX/LaTeX distro
> 
> Hello Vincent,
> 
> texinfo.tex is in Emacs' doc/misc/ directory.
> 
> >> 1. Certainly it must be possible to extract \texinfoversion from
> >>    texinfo.tex with standard tools (like sed or awk)?
> 
> > It is probably possible to play such tricks, but to do that you need
> > kpsewhich texinfo.tex in order to get the same texinfo.tex file full
> > path that a tex engine would use, so you need anyway a TeX/LaTeX
> > distro. Reading the version directly by processing the file with tex
> > does both the file finding with kpathsea lib and parsing it for the
> > version. And tex is not less standard than sed or awk, just more
> > cumbersome to install (and so I fully understand that some platform
> > won't have it).
> 
> TeX is not what most people would call a system package. Gentoo doesn't
> include it in its installation stages, and as I said before, we don't
> even support it on some of the more exotic architectures.
> 
> Besides, it is unreasonable to require users installing TeX as a
> prerequisite to build Emacs, when its sole purpose would be the texinfo
> version check in configure.
> 
> >> 2. Probably I am missing something, but why is the test even needed?
> >>    texinfo.tex is shipped with the Emacs sources so its version
> >>    should be well defined.
> 
> > The full story is that for a language like French (and for most
> > languages indeed), when you need accented letter (as in: Dès Noël, où
> > un zéphyr haï me vêt de glaçons würmiens, je dîne d’exquis rôtis de
> > bœuf au kir, à l’aÿ d’âge mûr, &cætera) and the document source is in
> > UTF-8 then some old version of texinfo may break the compilation
> > because the index engine splits two-byte characters into first byte
> > and create some non UTF-8  byte sequence.
> 
> > The test in texinfo.m4 just assumes that the default language does not
> > use UTF-8 but translations into other languages may do, so when a
> > recent tex/texinfo is not detected DOCLANGS is restricted to default.
> > The objective is the following : don't let documentation compilation
> > break the compilation.
> 
> > Actually it would be possible to write French manuals only with
> > ISO-8869-15 (aka latin 9) and avoid multibyte chars, and maybe some
> > day some manual in "default" language would not be in English but some
> > other language (Chinese ha ha ha) that need multibyte chars, or even
> > without becoming sacarstic, you may need some math symbol or some
> > emoji in a manual written in US English.
> 
> > Now, I am not sure about your problem, do you mean that w/o TeX
> > installed you can no longer build Emacs ?  I have not tested but
> > doesn't configure just makes some warning and anyway only info (not
> > needing TeX distro, this is a Perl program) manual are compiled.
> 
> The problem is that configure tries to execute the "tex" command, which
> may not be available on the system. In that case it will output the
> error message
> 
>    ./configure: line 14288: tex: command not found
> 
> and obviously the version test will not return the desired result.
> Also, any "command not found" message in configure output will trigger
> a QA warning in Gentoo's package manager (in fact, that's how I
> discovered this issue).
> 
> So, please pretty please find a different solution that doesn't require
> executing tex in configure.
> 
> Best regards,
> Ulrich