ci: install C++ build tools for Windows AOT

The Windows release jobs publish the executable with Native AOT, which
links the final binary with the MSVC linker (link.exe). The 1ES hosted
images do not ship the C++ toolchain, so every Windows leg fails with
"Platform linker not found" from Microsoft.NETCore.Native.Windows.targets.

Add a setup script that installs VS 2022 Build Tools with the single
VC.Tools component for the agent's architecture - x86.x64 on the Intel
legs (win-x86, win-x64), ARM64 on the Arm leg (win-arm64) - and run it
before the publish step. Installing just the architecture's component
keeps the download to the minimum that still provides link.exe and the
MSVC libraries; the .NET ILCompiler then discovers the toolchain through
the Visual Studio setup API.

Assisted-by: Claude Opus 4.8
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>

Author: mjcheetham

.azure-pipelines/release.yml

@@ -139,6 +139,14 @@ extends:
                   inputs:
                     packageType: sdk
                     version: '10.x'
+                # Native AOT links the published binary with the MSVC linker,
+                # which the hosted images do not ship by default. Install the
+                # VC++ build tools for the agent's architecture first.
+                - task: PowerShell@2
+                  displayName: 'Install C++ build tools for AOT'
+                  inputs:
+                    filePath: '.azure-pipelines/scripts/windows/setup-aot-build-tools.ps1'
+                    arguments: -Architecture ${{ dim.poolArch }}
                 # Publish the application payload.
                 - task: PowerShell@2
                   displayName: 'Publish payload'

.azure-pipelines/scripts/windows/setup-aot-build-tools.ps1

@@ -0,0 +1,83 @@
+# Install the MSVC C++ build tools that Native AOT needs to link the
+# git-credential-manager binary on Windows agents.
+#
+# Publishing with PublishAot=true invokes the platform linker (link.exe)
+# from the MSVC toolchain. The 1ES hosted images do not ship it by
+# default, so the AOT publish fails with "Platform linker not found"
+# (Microsoft.NETCore.Native.Windows.targets). See
+# https://aka.ms/nativeaot-prerequisites.
+#
+# Install VS 2022 Build Tools with the single VC.Tools component for the
+# agent's architecture - the smallest selection that provides link.exe
+# and the MSVC libraries: x86.x64 on Intel agents, ARM64 on Arm agents.
+# The .NET ILCompiler discovers the freshly installed toolchain through
+# the Visual Studio setup API, so no PATH manipulation is required.
+#
+# Intended to be invoked by a PowerShell@2 task with `filePath:` and a
+# single `-Architecture` argument (the matrix leg's poolArch). Diagnostics
+# are written to stdout so install failures can be diagnosed from the task
+# log.
+
+param(
+    [Parameter(Mandatory = $true)]
+    [ValidateSet('amd64', 'arm64')]
+    [string]$Architecture
+)
+
+$ErrorActionPreference = 'Stop'
+$ProgressPreference = 'SilentlyContinue'
+
+$component = if ($Architecture -eq 'arm64') {
+    'Microsoft.VisualStudio.Component.VC.Tools.ARM64'
+} else {
+    'Microsoft.VisualStudio.Component.VC.Tools.x86.x64'
+}
+
+$bootstrapper = "$env:TEMP\vs_BuildTools.exe"
+Write-Host "Downloading VS 2022 Build Tools bootstrapper..."
+Invoke-WebRequest -Uri 'https://aka.ms/vs/17/release/vs_BuildTools.exe' `
+    -OutFile $bootstrapper
+
+$vsArgs = @(
+    '--quiet', '--wait', '--norestart', '--nocache',
+    '--add', $component
+)
+Write-Host "Installing VS Build Tools (args: $($vsArgs -join ' '))..."
+$start = Get-Date
+$p = Start-Process -FilePath $bootstrapper -ArgumentList $vsArgs -Wait -PassThru
+$elapsed = (Get-Date) - $start
+Write-Host ("Installer exited with code {0} after {1:N0}s" -f `
+    $p.ExitCode, $elapsed.TotalSeconds)
+
+Write-Host ""
+Write-Host "===== Installer logs in `$env:TEMP ====="
+$logs = Get-ChildItem $env:TEMP -Filter 'dd_*.log' -ErrorAction SilentlyContinue |
+    Sort-Object LastWriteTime -Descending
+if ($logs) {
+    foreach ($log in $logs | Select-Object -First 5) {
+        Write-Host "----- $($log.FullName) (last 50 lines) -----"
+        Get-Content $log.FullName -Tail 50 -ErrorAction SilentlyContinue
+    }
+} else {
+    Write-Host "(no dd_*.log files found in `$env:TEMP)"
+}
+
+# 3010 = reboot required, treated as success.
+if ($p.ExitCode -notin 0, 3010) {
+    throw "VS Build Tools installer exited with code $($p.ExitCode)"
+}
+
+Write-Host ""
+Write-Host "===== Confirm $component via vswhere ====="
+$vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
+if (Test-Path $vswhere) {
+    $installPath = & $vswhere -latest -products * -requires $component `
+        -property installationPath | Select-Object -First 1
+    if ($installPath) {
+        Write-Host "VC tools installed at $installPath"
+    } else {
+        throw "$component not found after install (see logs above)"
+    }
+} else {
+    Write-Host "vswhere not found at $vswhere"
+}