Add ARM64 processor architecture support

[AlistairB]

#1

Superseeds #21

• Add support for ARM64
  • Install llvm12 on 8.10 + 9.0 for ARM64 as it is required. 9.2 does not require llvm.
• Improve the pattern used in docker based on other official images to better support multi-architecture.
• Add hadolint for the dockerfiles.
• Remove old dockerfiles (they don't serve much purpose and will trigger hadolint failures).

To Do

• Get Arm64 CI working.
  • Finish setting up drone.io to test the ARM64 build. Waiting on my drone.io account being enabled Mostly giving up in this.
  • I'm having some success with the emulated solution. Will pursue this more. Ok this works and is far better than nothing.
• Stack install is failing. Seems the gpg signature file is not correct for 2.7.1. Temporary solution, don't do gpg verification on aarch
• Even stack 2.7.1 seems to not work on ARM64. stack: /lib/aarch64-linux-gnu/libm.so.6: version 'GLIBC_2.29' not found (required by stack). I think the only solution is to remove stack entirely for ARM64. This is quite annoying though, as the haskell docker image smoke tests will check that stack is installed and working. Hmm
• Update official image tests to gracefully ignore stack test on ARM64. Official image tests only run on amd64, so this isn't needed.
• Update docker hub docs with ARM details + stack caveat.

[AlistairB]

Saving a record of what I used for the emulated approach before I squash. This failed because dpkg-architecture was still returning x86_64 when emulated.

  emulated:
    timeout-minutes: 30
    runs-on: ubuntu-latest
    name: ${{ matrix.ghc }}-${{ matrix.deb }}
    strategy:
      fail-fast: false
      matrix:
        ghc: ['9.2.1']
        deb: ['buster']
        include:
          # - ghc: '8.10.7'
          #   ghc_minor: '8.10'
          # - ghc: '9.0.1'
          #   ghc_minor: '9.0'
          - ghc: '9.2.1'
            ghc_minor: '9.2'
    steps:
      - uses: actions/checkout@v2
      - uses: actions/checkout@v2
        with:
          repository: docker-library/official-images
          path: official-images
      - name: docker build [${{ matrix.ghc }}]
        uses: uraimo/[email protected]
        with:
          arch: aarch64
          distro: ${{ matrix.deb }}
          githubToken: ${{ github.token }}
          dockerRunArgs: |
            --volume "${PWD}/official-images:/official-images"
          install: |
            apt-get update
            apt-get install -y curl
            curl -fsSL https://get.docker.com | sh
          run: |
            docker build --pull \
              -t haskell:${{ matrix.ghc }}-${{ matrix.deb }} \
              ${{ matrix.ghc_minor }}/${{ matrix.deb }}
            echo 'running official tests'
            ./official-images/test/run.sh haskell:${{ matrix.ghc }}-${{ matrix.deb }}
        uses: nick-invision/retry@v1
        with:
          timeout_minutes: 8
          max_attempts: 3
          command: |
            docker build --pull \
              -t haskell:${{ matrix.ghc }}-${{ matrix.deb }} \
              ${{ matrix.ghc_minor }}/${{ matrix.deb }}
      - uses: actions/checkout@v2
        with:
          repository: docker-library/official-images
          path: official-images
      - name: run official-images tests
        run: ./official-images/test/run.sh haskell:${{ matrix.ghc }}-${{ matrix.deb }}