During installation of mingw, at least, the git directories change, so
we need to reset the core.autocrlf config to false.
Once we finish checking out submodules, check that the line endings are
\n and not \r\n.
There is known issue where PowerShell is unreasonably slow downloading
files due to an issue with rendering the progress bar, see:
https://github.com/PowerShell/PowerShell/issues/2138
That issue is fixed in PowerShell Core (available in Azure Pipelines as
pwsh.exe) but it can also be worked around by setting:
$ProgressPreference = 'SilentlyContinue'
* Clean up the `install-windows-build-deps.yml` file and add some more
comments where appropriate.
* Add some comments to `run.yml`
* Don't fast path the `rustfmt` submodule, but we'll take care of that
later if necessary.
This commit is intended to go through and review/refactor the azure
pipelines configuration we have. The major changes are:
* The separate `{windows,macos,linux}.yml` files are now all merged into
one `run.yml`. This allows a shared "master flow" for all platforms
with divergence only where necessary.
* Some install steps have been separated as `install-*.yml` scripts,
where each script internally matches on the appropriate OS and then
delegates accordingly.
* Some various bits and pieces of cruft have been removed which were
artifacts of Travis's setup or similar.
