E.3 Using autoupdate to Modernize configure.ac

The autoupdate program updates a configure.ac file that calls Autoconf macros by their old names to use the current macro names. In version 2 of Autoconf, most of the macros were renamed to use a more uniform and descriptive naming scheme. See Macro Names, for a description of the new scheme. Although the old names still work (see Obsolete Macros, for a list of the old macros and the corresponding new names), you can make your configure.ac files more readable and make it easier to use the current Autoconf documentation if you update them to use the new macro names.

If given no arguments, autoupdate updates configure.ac, backing up the original version with the suffix ~ (or the value of the environment variable SIMPLE_BACKUP_SUFFIX, if that is set). If you give autoupdate an argument, it reads that file instead of configure.ac and writes the updated file to the standard output.

autoupdate accepts the following options:

--help

-h

Print a summary of the command line options and exit.

--version

-V

Print the version number of Autoconf and exit.

--verbose

-v

Report processing steps.

--debug

-d

Don’t remove the temporary files.

--force

-f

Force the update even if the file has not changed. Disregard the cache.

--include=dir

-I dir

Also look for input files in dir. Multiple invocations accumulate. Directories are browsed from last to first.

--prepend-include=dir

-B dir

Prepend directory dir to the search path. This is used to include the language-specific files before any third-party macros.