bug#17258: autogen.sh doesn't update stale autoconf files in build-aux

[Eli Zaretskii]

> From: Achim Gratz <Stromeko@nexgo.de>
> Date: Sun, 13 Apr 2014 13:30:43 +0200
> 
> [would you please not quote full email addresses?]

[Why?  And it's not me, it's Emacs.  And the list server mangles them
anyway.]

> Eli Zaretskii writes:
> >> My expectation would be that any call to autogen.sh would re-create
> >> these files.
> >
> > That's not enough (assuming we indeed want these files to be
> > re-created automatically): just running "make" will invoke the
> > autotools as needed.  In fact, after the initial invocation of
> > autogen.sh, you should normally never again need to run it by hand.
> 
> The Makefile (at least on GNU/Linux) actually calls autotools through
> autogen.sh and not directly.

GNUMakefile does, but not Makefile.in:

  $(srcdir)/configure: $(AUTOCONF_INPUTS)
          cd ${srcdir} && autoconf

  ACLOCAL_INPUTS = $(srcdir)/configure.ac $(srcdir)/m4/gnulib-comp.m4
  $(srcdir)/aclocal.m4: $(ACLOCAL_INPUTS)
          cd $(srcdir) && aclocal -I m4

  AUTOMAKE_INPUTS = $(srcdir)/aclocal.m4 $(srcdir)/lib/Makefile.am \
    $(srcdir)/lib/gnulib.mk
  $(srcdir)/lib/Makefile.in: $(AUTOMAKE_INPUTS)
          cd $(srcdir) && automake --gnu -a -c lib/Makefile