Improve --version output for old-style AC_INIT

[Noah Misch]

If a configure.{in,ac} uses an old-style `AC_INIT' or `AC_INIT(file)', configure
--version output presently looks like this:

$ ./configure --version

Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
This configure script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it.

With the appended patch, it looks like this:

$ ./configure --version
configure
generated by GNU Autoconf 2.59c

Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
This configure script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it.

That seems more helpful.  I know I have seen bug reports for this, but I do not
have a specific one handy for a citation.

2006-03-31  Noah Misch  <address@hidden>

        * lib/autoconf/general.m4 (_AC_INIT_VERSION): Emit script name and
        Autoconf version number despite a zero- or one-argument AC_INIT.

diff -urp -X dontdiff ac-clean/lib/autoconf/general.m4 
ac-oldinit/lib/autoconf/general.m4
--- ac-clean/lib/autoconf/general.m4    2006-03-16 08:33:18.000000000 -0500
+++ ac-oldinit/lib/autoconf/general.m4  2006-03-31 09:04:44.000000000 -0500
@@ -1087,13 +1087,10 @@ m4_divert_pop([HELP_END])dnl
 m4_define([_AC_INIT_VERSION],
 [m4_divert_text([VERSION_BEGIN],
 [if $ac_init_version; then
-  cat <<\_ACEOF])dnl
-m4_ifset([AC_PACKAGE_STRING],
-        [m4_divert_text([VERSION_BEGIN],
-                        [dnl
+  cat <<\_ACEOF
 m4_ifset([AC_PACKAGE_NAME], [AC_PACKAGE_NAME ])configure[]dnl
 m4_ifset([AC_PACKAGE_VERSION], [ AC_PACKAGE_VERSION])
-generated by m4_PACKAGE_STRING])])
+generated by m4_PACKAGE_STRING])
 m4_divert_text([VERSION_END],
 [_ACEOF
   exit