bug#47428: Problems building the up-to-date "devel" manual for the website

[Mathieu Othacehe]

>   MAKEINFO guile-library.info
> /tmp/guix-build-guile-lib-0.2.7.drv-0/guile-lib-0.2.7/build-aux/missing: line 
> 81: makeinfo: command not found

Looks like the devel manual generation is fixed. The guile-lib@0.2.7
build failure above only happens when generating the stable manual.

In that case, doc/build.scm uses guile-lib/htmlprag-fixed instead of the
plain guile-lib like on master (since
25db3b2f8bb4a18e9405d2cd32aa899e0007f236).

This causes the build failure. However, we do not have this makeinfo
error on the master guile-lib. That's because the docs are not compiled
for a reason I don't understand.

When running manually "make all" from the build directory, I experience
the same error:

--8<---------------cut here---------------start------------->8---
  MAKEINFO guile-library.info
/tmp/guix-build-guile-lib-0.2.7.drv-0/guile-lib-0.2.7/build-aux/missing: line 
81: makeinfo: command not found
--8<---------------cut here---------------end--------------->8---

that is solved by adding "texinfo" to the native-inputs. 

Mathieu