[release/5.0] Enable MUSL ARM support (#27942)

This change adds support for building MUSL ARM packages of ASP.NET Core.

.azure/pipelines/ci.yml

@@ -525,6 +525,40 @@ stages:
       parameters:
         inputName: Linux_musl_x64
 
+  # Build Linux Musl ARM
+  - template: jobs/default-build.yml
+    parameters:
+      jobName: Linux_musl_arm_build
+      jobDisplayName: "Build: Linux Musl ARM"
+      agentOs: Linux
+      useHostedUbuntu: false
+      container: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-18.04-cross-arm-alpine-20200827125937-14441ae
+      buildScript: ./build.sh
+      buildArgs:
+        --arch arm
+        --os-name linux-musl
+        --pack
+        --all
+        --no-build-nodejs
+        --no-build-java
+        -p:OnlyPackPlatformSpecificPackages=true
+        -p:AssetManifestFileName=aspnetcore-Linux_musl_arm.xml
+        $(_BuildArgs)
+        $(_PublishArgs)
+        $(_InternalRuntimeDownloadArgs)
+      installNodeJs: false
+      installJdk: false
+      artifacts:
+      - name: Linux_musl_arm_Logs
+        path: artifacts/log/
+        publishOnError: true
+        includeForks: true
+      - name: Linux_musl_arm_Packages
+        path: artifacts/packages/
+  - template: jobs/codesign-xplat.yml
+    parameters:
+      inputName: Linux_musl_arm
+
   # Build Linux Musl ARM64
   - template: jobs/default-build.yml
     parameters:
@@ -758,6 +792,7 @@ stages:
             - CodeSign_Xplat_Linux_arm
             - CodeSign_Xplat_Linux_arm64
             - CodeSign_Xplat_Linux_musl_x64
+            - CodeSign_Xplat_Linux_musl_arm
             - CodeSign_Xplat_Linux_musl_arm64
           # In addition to the dependencies above, ensure the build was successful overall.
           - Source_Build

Directory.Build.props

@@ -162,6 +162,7 @@
       win-arm64;
       osx-x64;
       linux-musl-x64;
+      linux-musl-arm;
       linux-musl-arm64;
       linux-x64;
       linux-arm;

eng/Dependencies.props

@@ -94,6 +94,7 @@ and are generated based on the last package release.
     <LatestPackageReference Include="Microsoft.NETCore.App.Runtime.linux-arm" />
     <LatestPackageReference Include="Microsoft.NETCore.App.Runtime.linux-arm64" />
     <LatestPackageReference Include="Microsoft.NETCore.App.Runtime.linux-musl-x64" />
+    <LatestPackageReference Include="Microsoft.NETCore.App.Runtime.linux-musl-arm" />
     <LatestPackageReference Include="Microsoft.NETCore.App.Runtime.linux-musl-arm64" />
   </ItemGroup>
 

src/Framework/App.Runtime/src/Microsoft.AspNetCore.App.Runtime.csproj

@@ -92,7 +92,7 @@ This package is an internal implementation of the .NET Core SDK and is not meant
     <PathSeparator Condition="'$(PathSeparator)' == ''">:</PathSeparator>
     <PathSeparator Condition=" '$(TargetOsName)' == 'win' ">%3B</PathSeparator>
 
-    <CrossCompileDirectory Condition=" '$(TargetRuntimeIdentifier)' == 'linux-arm' ">x64_arm</CrossCompileDirectory>
+    <CrossCompileDirectory Condition=" '$(TargetRuntimeIdentifier)' == 'linux-arm' OR '$(TargetRuntimeIdentifier)' == 'linux-musl-arm'">x64_arm</CrossCompileDirectory>
     <CrossCompileDirectory Condition=" '$(TargetArchitecture)' == 'arm64' AND '$(BuildArchitecture)' != 'arm64' ">x64_arm64</CrossCompileDirectory>
     <CrossCompileDirectory Condition=" '$(TargetRuntimeIdentifier)' == 'win-arm' ">x86_arm</CrossCompileDirectory>