Add CI job for 2-stage build with -mt mode

.vsts-dotnet-ci.yml

@@ -245,6 +245,36 @@ jobs:
     continueOnError: true
     condition: eq(variables.onlyDocChanged, 0)
 
+- job: BootstrapMSBuildWithMTMode
+  displayName: "Linux Core Multithreaded Mode"
+  pool:
+    vmImage: 'ubuntu-latest'
+  timeoutInMinutes: 120
+  steps:
+  - template: azure-pipelines/check-documentation-only-change.yml
+  - ${{ if eq(variables['System.TeamProject'], 'DevDiv') }}:
+    - task: Bash@3
+      displayName: Setup Private Feeds Credentials
+      inputs:
+        filePath: $(Build.SourcesDirectory)/eng/common/SetupNugetSources.sh
+        arguments: $(Build.SourcesDirectory)/NuGet.config $Token
+      env:
+        Token: $(dn-bot-dnceng-artifact-feeds-rw)
+  - bash: sudo apt-get update
+  - bash: sudo apt-get install -y libxml2
+  - bash: . 'eng/cibuild_bootstrapped_msbuild.sh' --onlyDocChanged $(onlyDocChanged) --skipTests --stage2Properties '/mt'
+    displayName: 'Build with bootstrapped MSBuild and -mt mode'
+    condition: eq(variables.onlyDocChanged, 0)
+    env:
+      MSBUILDUSESERVER: "1"
+  - task: PublishBuildArtifacts@1
+    displayName: 'Publish Artifact: logs'
+    inputs:
+      PathtoPublish: 'artifacts/log/Debug'
+      ArtifactName: 'MTModeOnLinux build logs'
+    continueOnError: true
+    condition: always()
+
 - job: FullReleaseOnWindows
   displayName: "Windows Full Release (no bootstrap)"
   variables:

eng/cibuild_bootstrapped_msbuild.sh

@@ -4,8 +4,10 @@ configuration="Debug"
 host_type="core"
 build_stage1=true
 onlyDocChanged=0
+skipTests=false
 properties=
 extra_properties=
+stage2Properties=
 
 SOURCE="${BASH_SOURCE[0]}"
 while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
@@ -34,6 +36,14 @@ while [[ $# -gt 0 ]]; do
       onlyDocChanged=$2
       shift 2
       ;;
+    --skiptests)
+      skipTests=true
+      shift 1
+      ;;
+    --stage2properties)
+      stage2Properties=$2
+      shift 2
+      ;;
     *)
       properties="$properties $1"
       shift 1
@@ -88,10 +98,15 @@ export DOTNET_HOST_PATH="$_InitializeDotNetCli/dotnet"
 # When using bootstrapped MSBuild:
 # - Turn off node reuse (so that bootstrapped MSBuild processes don't stay running and lock files)
 # - Create bootstrap environment as it's required when also running tests
+# - stage2Properties are passed to all Stage 2 builds since some MSBuild switches (like /mt) may not work with the SDK MSBuild used in Stage 1
 if [ $onlyDocChanged = 0 ]
 then
-    . "$ScriptRoot/common/build.sh" --restore --build --test --ci --nodereuse false --configuration $configuration $properties $extra_properties
-
+    if [ "$skipTests" = true ]
+    then
+        . "$ScriptRoot/common/build.sh" --restore --build --ci --nodereuse false --configuration $configuration $properties $extra_properties $stage2Properties
+    else
+        . "$ScriptRoot/common/build.sh" --restore --build --test --ci --nodereuse false --configuration $configuration $properties $extra_properties $stage2Properties
+    fi
 else
-    . "$ScriptRoot/common/build.sh" --restore --build --ci --nodereuse false --configuration $configuration /p:CreateBootstrap=false $properties $extra_properties
+    . "$ScriptRoot/common/build.sh" --restore --build --ci --nodereuse false --configuration $configuration /p:CreateBootstrap=false $properties $extra_properties $stage2Properties
 fi