azure-pipelines.yml: switch from host build to container build

This has two main advantages: firstly it means that the Dockerfile is being tested
as part of the pipeline when changes are merged into master, and secondly it allows
testing of Linux builds without requiring a separate job for Docker that can consume
even more CI minutes.

In order to test the container image it is necessary to manually start the build
image using docker run, execute the tests, and then copy the results back to the
host ready for publishing.

Note that since the base OS image is now handled by docker we can switch the host
to use the 'ubuntu-latest' image rather than the older 'ubuntu-20.04' image.

azure-pipelines.yml

@@ -5,34 +5,33 @@ jobs:
 
 - job: Linux
   pool:
-    vmImage: 'ubuntu-20.04'
+    vmImage: 'ubuntu-latest'
   timeoutInMinutes: 90
   steps:
   - checkout: self
     submodules: true
-  - script: |
-      sudo apt-get update
-      DEBIAN_FRONTEND=noninteractive sudo apt-get install -y \
-        cmake libgmp-dev libmpfr-dev libmpc-dev \
-        libboost-all-dev bison texinfo \
-        ruby flex curl
-    displayName: 'Install prerequisites'
-  - script: |
-      mkdir build
-      cd build
-      ../build-toolchain.bash
+  - task: Docker@2
+    inputs:
+      command: build
+      repository: ghcr.io/mcayland/retro68-build
+      tags: latest
+      arguments: --target build
     displayName: 'Build'
   - script: |
-      cd build
-      curl -L -O https://github.com/autc04/executor/releases/download/v0.1.0/Executor2000-0.1.0-Linux.tar.bz2
-      tar xfvj Executor2000-0.1.0-Linux.tar.bz2 Executor2000-0.1.0-Linux/bin/executor-headless
-      echo "executor-path=`pwd`/Executor2000-0.1.0-Linux/bin/executor-headless" > ~/.LaunchAPPL.cfg
-      echo "emulator=executor" >> ~/.LaunchAPPL.cfg
-      ctest --no-compress-output -T test -E Carbon || true
+      docker run --name retro68-build --rm -i -d ghcr.io/mcayland/retro68-build:latest
+      docker exec -i retro68-build /bin/bash <<"EOF"
+        cd /Retro68-build
+        curl -L -O https://github.com/autc04/executor/releases/download/v0.1.0/Executor2000-0.1.0-Linux.tar.bz2
+        tar xfvj Executor2000-0.1.0-Linux.tar.bz2 Executor2000-0.1.0-Linux/bin/executor-headless
+        echo "executor-path=`pwd`/Executor2000-0.1.0-Linux/bin/executor-headless" > ~/.LaunchAPPL.cfg
+        echo "emulator=executor" >> ~/.LaunchAPPL.cfg
+        ctest --no-compress-output -T test -E Carbon || true
+      EOF
+      mkdir build && docker cp retro68-build:/Retro68-build/Testing build
+      docker stop retro68-build
     displayName: Run Tests using Executor 2000
   - task: PublishTestResults@2
     inputs:
       testResultsFormat: 'CTest'
       testResultsFiles: build/Testing/**/*.xml
       buildPlatform: 'x86_64-linux'
-