[RFA] Allow WARNING: spam to be disabled by the user.

[Klee Dienes]

The following message from autoconf:

WARNING:    Using auxiliary files such as `acconfig.h', `config.h.bot'
WARNING:    and config.h.top, to define templates for `config.h.in'
WARNING:    is deprecated and discouraged.
WARNING:
WARNING:    Using the third argument of `AC_DEFINE' and
WARNING:    `AC_DEFINE_UNQUOTED' allows to define a template without
WARNING:    `acconfig.h:
WARNING:
WARNING:      AC_DEFINE([NEED_MAIN], 1,
WARNING:                [Define if a function \`main\' is needed.])

can get really grating, when one is just trying to reconfigure a huge 
source tree, and doesn't plan to remove the template files immediately. 
 Unfortunately, there's no way to turn it off ... autoheader accepts 
the -Wall/none/etc. options, but doesn't honor them.

The following patch adds -Wall/none/etc. support to autoheader.

autoheader-warnings.txt
Description: Text document