[build2] Issues with my first attempt at build2 CI

[Klaim - Joël Lamotte]

On Wed, 7 Nov 2018 at 12:26, Boris Kolpackov <boris at codesynthesis.com> wrote:
> I only get this error if I forget to checkout the gtest-origin
> submodule ;-).

*palmface*

I forget Every. Single. Time. :P

I'm getting used too much to automatic downloads&compiles.
Sorry about that.

> I've also improved the diagnostics:
>
> buildfile:111:15: error: no prerequisites in prerequisite-specific variable assignment

Though it makes sense locally, it's still super obscure when you know
the actual source of the error.

Would it make sense to have an error when opening a scope to a
directory that do not exist?
That would catch the submodule missing.

Joël