Automake 2.50 migration strategy, as implemented

[pfaffben@msu.edu (Ben Pfaff)]

I am currently uploading the new version of autoconf and
autoconf2.13.  These attempt to automatically select the desired
version of Autoconf utilities at the time they are run.  In my
simple tests, they work well.  We'll see how they do in practice,
but I suspect that, except for possible minor bugs in the
wrappers, they will work well there too.

All that autobuilder maintainers, etc., should need to do, is to
make sure that they install autoconf2.13 as well as the new
autoconf.  This should not be challenging because the new
autoconf Recommends: autoconf2.13 for now.  (I intend to demote
the recommendation to a suggestion, then remove it, over the next
year or so, as it gradually becomes less necessary.)

Below is the README.Debian from autoconf2.13.

Comments?

Autoconf 2.13							-*- text -*-
-------------

This is the Debian packaging of Autoconf 2.13, an obsolete release of
the Autoconf system for creating configuration scripts using
templates.  This version of Autoconf is obsolete and its use is
deprecated.

It is troublesome to determine which programs need this compatibility
package and adapt them for it.  As a result, this package has wrappers
for autoconf, autoheader, and autoreconf.  Each of these attempts to
detect which Autoconf is needed and run the correct version of the
tool.

There are no wrappers for autoupdate, autoscan, or ifnames.  These are
not used during a package build.  Choose the proper version by hand.

The following heuristics are used to choose an Autoconf version:

	* If file `configure.ac' exists, Autoconf 2.50 is used.
          Autoconf 2.13 used the name `configure.in' instead, but
          version 2.50 supports both.  

          (Usually autoconf is run without nonoption arguments.  If a
          filename is supplied on the command line, then version 2.50
          is used if the filename ends in `.ac'.)

	* Otherwise, `configure.in' (or the file specified on the
          command line, if any) is read.  It is checked for the
          presence of an AC_PREREQ directive.  If it specifies a
          minimum version higher than 2.13, Autoconf 2.50 is used.

	* Otherwise, Autoconf 2.13 is used.

To force Autoconf 2.13 to be used, name the Autoconf input file
`configure.in' and omit the use of AC_PREREQ() or specify a minimum
version of 2.13 or earlier.  To force Autoconf 2.50 to be used, name
the input file `configure.ac' or use AC_PREREQ(2.50).

I recommend not calling the programs autoconf2.13 or autoconf2.50,
etc., directly, instead of through the wrappers.  When used with
programs like Automake, these direct calls won't propagate through
into the Makefile, so later re-autoconf'ings won't use the correct
version.  It's better to use one of the methods explained above to
force a particular version.

-- 
"Implementation details are beyond the scope of the Java virtual
 machine specification.  One should not assume that every virtual
 machine implementation contains a giant squid."
--"Mr. Bunny's Big Cup o' Java"