[cmake-developers] ExternalProject + git submodule sync

[Brad King]

On 03/29/2016 10:17 AM, Ben Boeckel wrote:
> I'd like to bump the minimum ExternalProject requirement to 1.8.1 from
> November 2012 (current requirement is 1.6.5 from October 2009). The
> reason is that this release introduced the `git submodule sync
> --recursive` command

Rather than a hard requirement we should adapt to any version of
Git we find, perhaps with degraded functionality.

> The usecase is for updates to the repo where the submodule URL
> changes after an update.
[snip]
> Or is it better to make the `git submodule sync --recursive`
> conditional?

Might a user want to change the url used locally?  If so then we
need a way to turn off the automatic sync, though I think making
it default is reasonable.

-Brad