Picked (guix build emacs-utils) for now, it's done to avoid huge
rebuilds, while testing, later we can move it to (guix build utils).

Also, temporary added pandoc and texinfo to native-inputs for
emacs-build-system, otherwise I would need to update inputs for almost
every emacs-* package.  Need to figure out what to do with this.

>
>> Attaching the latest version of the documentation-files patch I have
> Looking at this patch, perhaps we'd also have to allow customizing
> command line options.  Also, as for installing, I think this should be
> handled by the install phase, which already has includes
> "^[^/]*\\.info$" and "^doc/.*\\.info$" by default.  Thus, you only need
> to build documentation before the install phase.

That's right, but in the new iteration (v3) of build-documentation phase
I use find-root-library-file, which expects to be executed when elpa
directory is already available, so I can't do it before install phase
and need to manually install info files.

Also, current build phases order is a little confusing, a lot of builds
happens after install phase, directly in output directory:

`set-SOURCE-DATE-EPOCH'
`set-paths'
`install-locale'
`unpack'
`expand-load-path'
`patch-usr-bin-file'
`patch-source-shebangs'
`patch-generated-file-shebangs'
`check'
`install'
`make-autoloads'
`enable-autoloads-compilation'
`patch-el-files'
`ensure-package-description'
`build'
`validate-compiled-autoloads'
`build-documentation'
`move-doc'
`patch-shebangs'
`strip'
`validate-runpath'
`validate-documentation-location'
`delete-info-dir-file'
`patch-dot-desktop-files'
`make-dynamic-linker-cache'
`install-license-files'
`reset-gzip-timestamps'
`compress-documentation'

What if instead of install phase we will use
create-tmp-lisp-and-documentation-directories phase (or something more
meaningful) to make a temporary directory, where we will build all the
stuff and after that, at the end of the build process will install
everything from this temporary directory to the store?  This way
emacs-build-system will become more usual and easier to understand and
predict.

-- 
Best regards,
Andrew Tropin