Bison requires at least Autoconf 2.58

[Paul Eggert]

I tried building Bison with Autoconf 2.57 and it didn't work: it output
"autom4te: unknown language: Autoconf-without-aclocal-m4".  I don't
recall what this means, but rather than dive into it I simply installed
this patch.

2004-05-27  Paul Eggert  <address@hidden>

        * configure.ac (AC_PREREQ): Bump to 2.58, since 2.57 doesn't work
        (it fails with a Autoconf-without-aclocal-m4 diagnostic).

Index: configure.ac
===================================================================
RCS file: /cvsroot/bison/bison/configure.ac,v
retrieving revision 1.45
diff -p -u -r1.45 configure.ac
--- configure.ac        26 May 2004 19:25:21 -0000      1.45
+++ configure.ac        27 May 2004 07:32:41 -0000
@@ -17,8 +17,9 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 # 02111-1307  USA
 
-# We need a recent Autoconf to run a recent Autotest.
-AC_PREREQ(2.57)
+# We need a recent Autoconf to avoid the message
+# "autom4te: unknown language: Autoconf-without-aclocal-m4".
+AC_PREREQ(2.58)
 
 AC_INIT([GNU Bison], [1.875e], address@hidden)
 AC_CONFIG_AUX_DIR([config])