[libvirt] [PATCH] use gnulib via a submodule

[Jim Meyering]

Daniel P. Berrange wrote:
...
>> From: Jim Meyering <meyering at redhat.com>
>> Date: Tue, 7 Jul 2009 11:22:52 +0200
>> Subject: [PATCH 5/7] make .gnulib a submodule
>>
>> This makes it so we record (via a git submodule)
>> a snapshot of whatever version of gnulib we're using,
>> and none of gnulib sources are in the libvirt repository.
>> The result is that we have as much reproducibility as when
>> we version-controlled imported copies of the gnulib sources,
>> but without the hassle of the manual process we used when
>> syncing with upstream.
>>
>> Note that when you clone libvirt, you get only the libvirt
>> repository, but when you first run ./bootstrap, it clones
>> gnulib (at the SHA1 recorded via the submodule), creating
>> the .gnulib/ hierarchy.  Then, the bootstrap script runs
>> gnulib-tool to populate gnulib/ with the files that make
>> up the selected modules.
>
>
> I think perhaps we should wire this into the autogen.sh
> script. People are used to just cloning a repository and
> running autogen.sh to get things setup, so it would cause
> unneccessary confusion to also require them to run bootstrap
> seprately.

One reason not to do this (at least not unconditionally)
is that it takes pretty long.  I've just timed it at 31 seconds,
even though everything is already downloaded.
That happens to be the same duration (to the second!)
of the existing ./autogen.sh script.