top-level configure options, --help

[NightStrike]

On 02 Jan 2008 08:54:39 -0800, Ian Lance Taylor <iant@google.com> wrote:
> NightStrike <nightstrike@gmail.com> writes:
>
> > I noticed that --with-sysroot is not listed in --help for the top
> > level configure, but --with-build-sysroot is.  Is that on purpose?
> > Should the former not be used at all in place of the latter?
>
> This is an unfortunate artifact of autoconf --help handling with
> recursive configure scripts.  You'll see both mentioned in the output
> of gcc/configure --help.  --with-build-sysroot needs to be handled at
> the top level in order to pass down the --sysroot option when
> compiling libraries; therefore, it appears in the top level --help
> output.  --with-sysroot does not need to be handled at the top level;
> therefore, it does not appear in the top level --help output.

If that's the case, there must be more options as well that are not
present in top level's --help that really are options that the user
would actually use.  I would think that a simple AS_HELP_STRING macro
in the top level configure would accomplish this.  That, or a blank
ARG_WITH macro.. something like:

AC_ARG_WITH([sysroot],
  [AS_HELP_STRING([--with-sysroot],
    [Sets the sysroot])],
  [],
  [])

You could list the option in the top level configure, but give it no
action.  This is a benefit to the user, so that the top level
configure --help contains all the options that a user would use.