Update autoconf for gas

[DJ Delorie]

> DJ, is this version OK?
> 
> > 2003-08-28  Daniel Jacobowitz  <drow@mvista.com>
> > 
> > 	* configure.in: Update AC_PREREQ to 2.57.  Use AC_CONFIG_FILES
> > 	and AC_CONFIG_COMMANDS instead of the three-argument AC_OUTPUT.
> > 	Specify AC_CONFIG_AUX_DIR.
> > 	* configure: Regenerated with autoconf 2.57.
> > 	* aclocal.m4: Regenerated with aclocal-1.7.
> > 	* Makefile.in, doc/Makefile.in: Regenerated with automake-1.7.

Ok.