Add MSYS2 and some of its packages to Windows image

I need MSYS2 added to the windows.vs2022.amd64 image, plus ideally a handful of packages - this is part of the regular AzDO Hosted pool, but seems not to be present on our pool’s images. Right now, I’m using:

(New-Object System.Net.WebClient).DownloadFile('https://github.com/msys2/msys2-installer/releases/download/nightly-x86_64/msys2-base-x86_64-latest.sfx.exe', 'msys2.exe')
.\msys2.exe -y -oC:\  # Extract to C:\msys64
Remove-Item msys2.exe  # Delete the archive again
C:\msys64\usr\bin\bash -lc ' '
C:\msys64\usr\bin\bash -lc 'pacman --noconfirm -Syuu'
C:\msys64\usr\bin\bash -lc 'pacman --noconfirm -S msys/make msys/ninja msys/cmake msys/diffutils'

on a per-build basis. We should probably bake it in, to avoid the repeated downloads & extra point of failure.

(These instructions are pretty much direct from the MSYS2 website page on CI integration, https://www.msys2.org/docs/ci/#other-systems )

Release Note Category

• Feature changes/additions
• Bug fixes
• Internal Infrastructure Improvements

Release Note Description

[directhex]

👍 my build is green with 1es-windows-2022 and:

        - powershell: |
            C:\msys64\usr\bin\bash -lc ' '
            C:\msys64\usr\bin\bash -lc 'pacman --noconfirm -Syuu'
            C:\msys64\usr\bin\bash -lc 'pacman --noconfirm -S msys/make msys/ninja msys/cmake msys/diffutils'
          displayName: Install MSYS2 packages (GNU Make and related)

[mmitche]

Yeah I think this is an improvement. Certainly an improvement over downloading a nightly build of msys2