Dear Guix,

Due to an old Automake version (1.13), running the `./configure' phase on
CentOS 7 fails with:

> autoreconf: running: automake --add-missing --copy --force-missing
> configure.ac:21: warning: The 'AM_PROG_MKDIR_P' macro is deprecated, and its use is discouraged.
> configure.ac:21: You should use the Autoconf-provided 'AC_PROG_MKDIR_P' macro instead,
> configure.ac:21: and use '$(MKDIR_P)' instead of '$(mkdir_p)'in your Makefile.am files.
> Makefile.am:422: warning: AM_GNU_GETTEXT used but 'po' not in SUBDIRS
> automake: error: cannot open < ./%D%/guix.texi: No such file or directory
> autoreconf: automake failed with exit status: 1

(It does not replace %D% with the appropriate directory..)

The attached patch replaces each instance of %D%, which I believe stands
for the current subdirectory from the project root, with the appropriate
directory.  With these changes, I've been able to compile GNU Guix on
CentOS 7.

I am not sure how this change impacts custom configure options, so I
would like to ask someone with more Automake knowledge and experience to
elaborate on the possible downsides of applying this patch.

If this change is acceptable to the project, I will update the commit
message to a more detailed and conforming message.  Suggestions are
welcome here though.

What do you think about making Guix compilable on this "stable"
distribution? :-)

Thanks!

Kind regards,
Roel Janssen