Re: arm64 support for stuart

["Gerd Hoffmann" <kraxel@redhat.com>]

  Hi,

> Given that nasm is x86 specific, we should be able to work around this
> by moving the nasm_ext_dep.yaml file into the right place.

Overall stuart feels kind of alien to linux.  It just goes download
stuff from the internet, even in case the tools are already available
locally.  Oliver fixed some (but not all) of these when moving CI over
to using containers.  IIRC at least the cross compilers are just the
standard fedora cross compiler packages now.

While being at it:  edk2-pytool-library fails to build with network
access turned off[1] because it tries to download vswhere.exe from the
internet.  Even when building on linux.

> Then, if/when mu_nasm for arm64 becomes available, we will also be
> able to build OVMF from arm64 (although I am probably the only person
> in the world who does that regularly.)

Fedora build system does that too.  We have a patch to make x86 cross
builds work like arm cross builds, by just setting GCC5_${ARCH}_PREFIX
environment variable:
  https://github.com/kraxel/edk2/commit/6b2ca6f01bb76a3b9632e902b4bf0ef9e912ce40

Guess I should submit that one for upstream inclusion ;)

> iasl is a different matter, as we need it to build for arm64 as well.
> iasl is already available in the arm64 distros, so as I see it, there
> are 3 options here:
> - build iasl for Linux/arm64 and add it to the nuget repo
> - allow a fallback to system-wide iasl (how?)

Just use the system-wide tools is the best option IMHO.  The packages
are available in Fedora (other distros should be have them too), on both
x86_64 and aarch64, we only need to add them to the CI container image.
So why bother adding nuget builds?

That is also less fragile than downloading them on each CI run and have
checks fail now and then due to network problems.

Is it possible to run github actions (used to build containers) and
azure pipelines on aarch64 systems?  So we could move ArmVirt CI from
x86 cross builds to native arm builds?

take care,
  Gerd

[1] Offline builds are standard for linux distro builds to make sure
    all sources needed are to produce the binary package are actually
    included in the source package.