Add setup-dev-env.ps1 to validate development prerequisites

Checks for CMake, Visual Studio components (Clang, ATL, MSBuild),
Windows SDK 26100, Developer Mode, and optional tools (WinDbg, Python).
Reports missing items with install instructions.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Ben Hillis

doc/docs/dev-loop.md

@@ -2,6 +2,8 @@
 
 ## Prerequisites 
 
+You can verify all prerequisites are installed by running `tools\setup-dev-env.ps1`.
+
 The following tools are required to build WSL: 
 
 - CMake >= 3.25

tools/setup-dev-env.ps1

@@ -0,0 +1,132 @@
+<#
+.SYNOPSIS
+    Checks that all prerequisites for building WSL are installed.
+.DESCRIPTION
+    Validates the development environment and reports missing tools
+    with installation instructions. Run this before your first build.
+.EXAMPLE
+    .\tools\setup-dev-env.ps1
+#>
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$script:Errors = 0
+
+function Check($Name, $Result, $Fix, [switch]$Optional)
+{
+    if ($Result)
+    {
+        Write-Host "  [OK] $Name" -ForegroundColor Green
+    }
+    elseif ($Optional)
+    {
+        Write-Host "  [OPTIONAL] $Name" -ForegroundColor DarkYellow
+        Write-Host "    -> $Fix" -ForegroundColor Yellow
+    }
+    else
+    {
+        Write-Host "  [MISSING] $Name" -ForegroundColor Red
+        Write-Host "    -> $Fix" -ForegroundColor Yellow
+        $script:Errors++
+    }
+}
+
+Write-Host ""
+Write-Host "WSL Development Environment Check" -ForegroundColor Cyan
+Write-Host "==================================" -ForegroundColor Cyan
+Write-Host ""
+
+# --- CMake ---
+Write-Host "Build Tools:" -ForegroundColor White
+$cmake = Get-Command "cmake" -ErrorAction SilentlyContinue
+$cmakeVersion = $null
+$cmakeOk = $false
+if ($cmake)
+{
+    $cmakeVersion = [version]((cmake --version | Select-Object -First 1) -replace '[^0-9.]', '')
+    $cmakeOk = $cmakeVersion -ge [version]"3.25"
+}
+Check "CMake >= 3.25$(if ($cmakeVersion) { " (found $cmakeVersion)" })" $cmakeOk "winget install Kitware.CMake"
+
+# --- Visual Studio ---
+$vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
+$vsInstall = $null
+if (Test-Path $vswhere)
+{
+    $vsInstall = & $vswhere -latest -property installationPath 2>$null
+}
+Check "Visual Studio 2022+" ($null -ne $vsInstall) "Install Visual Studio 2022: https://visualstudio.microsoft.com/"
+
+# --- VS Components (only check if VS is found) ---
+if ($vsInstall)
+{
+    Write-Host ""
+    Write-Host "Visual Studio Components:" -ForegroundColor White
+
+    $installedComponents = @(& $vswhere -latest -property catalog_productLineVersion 2>$null)
+    $vsComponents = & $vswhere -latest -format json 2>$null | ConvertFrom-Json
+
+    # Check for specific required components via their markers
+    $clangPath = Join-Path $vsInstall "VC\Tools\Llvm\x64\bin\clang-format.exe"
+    Check "C++ Clang Compiler for Windows" (Test-Path $clangPath) "VS Installer -> Modify -> Individual Components -> C++ Clang Compiler for Windows"
+
+    $atlPath = Get-ChildItem -Path (Join-Path $vsInstall "VC\Tools\MSVC") -Filter "atlbase.h" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 1
+    Check "C++ ATL for latest v143 tools" ($null -ne $atlPath) "VS Installer -> Modify -> Individual Components -> C++ ATL for latest v143 build tools"
+
+    $msbuild = Get-Command "msbuild" -ErrorAction SilentlyContinue
+    if (-not $msbuild)
+    {
+        $msbuild = Get-ChildItem -Path $vsInstall -Filter "MSBuild.exe" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 1
+    }
+    Check "MSBuild" ($null -ne $msbuild) "VS Installer -> Modify -> Individual Components -> MSBuild"
+}
+
+# --- Windows SDK ---
+Write-Host ""
+Write-Host "Windows SDK:" -ForegroundColor White
+$sdkPath = "${env:ProgramFiles(x86)}\Windows Kits\10\Include\10.0.26100.0"
+Check "Windows SDK 26100" (Test-Path $sdkPath) "VS Installer -> Modify -> Individual Components -> Windows 11 SDK (10.0.26100.0)"
+
+# --- Developer Mode / Symlinks ---
+Write-Host ""
+Write-Host "System Configuration:" -ForegroundColor White
+
+$devMode = $false
+try
+{
+    $devModeReg = Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" -Name "AllowDevelopmentWithoutDevLicense" -ErrorAction SilentlyContinue
+    $devMode = $devModeReg -and $devModeReg.AllowDevelopmentWithoutDevLicense -eq 1
+}
+catch {}
+
+$isAdmin = ([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
+Check "Developer Mode or Admin$(if ($devMode) { ' (Developer Mode)' } elseif ($isAdmin) { ' (Administrator)' })" ($devMode -or $isAdmin) "Settings -> System -> For developers -> Developer Mode"
+
+# --- Optional tools ---
+Write-Host ""
+Write-Host "Optional Tools:" -ForegroundColor White
+
+$windbg = Get-Command "WinDbgX.exe" -ErrorAction SilentlyContinue
+Check "WinDbg (for /attachdebugger)" ($null -ne $windbg) "winget install Microsoft.WinDbg" -Optional
+
+$python = Get-Command "python3" -ErrorAction SilentlyContinue
+if (-not $python) { $python = Get-Command "python" -ErrorAction SilentlyContinue }
+Check "Python 3 (for validation scripts)" ($null -ne $python) "winget install Python.Python.3.13" -Optional
+
+# --- Summary ---
+Write-Host ""
+if ($script:Errors -eq 0)
+{
+    Write-Host "All prerequisites found. Ready to build!" -ForegroundColor Green
+    Write-Host ""
+    Write-Host "  cmake ."
+    Write-Host "  cmake --build . -- -m"
+    Write-Host ""
+}
+else
+{
+    Write-Host "$($script:Errors) prerequisite(s) missing. Install them and re-run this script." -ForegroundColor Red
+    Write-Host ""
+    exit 1
+}