feat: Add Profile-Guided Optimization (PGO) build support

Implements two-stage PGO build system with CMake integration and
automated build scripts for Windows, Linux, and macOS. Supports
MSVC, GCC, and Clang compilers.

PGO enables runtime profiling-based optimizations for improved
emulator performance. Includes helper scripts to streamline the
build workflow and resolve platform-specific issues.

Signed-off-by: Zephyron <zephyron@citron-emu.org>

fix-pgo-dll.ps1

@@ -0,0 +1,174 @@
+# SPDX-FileCopyrightText: 2025 citron Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# Fix PGO DLL Script for Citron (Windows)
+# This script helps locate and copy the required pgort140.dll for MSVC PGO builds
+
+param(
+    [Parameter()]
+    [string]$OutputDir = "build\bin\Release",
+    
+    [Parameter()]
+    [switch]$Help
+)
+
+function Show-Usage {
+    Write-Host @"
+Usage: .\fix-pgo-dll.ps1 [OPTIONS]
+
+This script helps fix the "pgort140.DLL was not found" error by locating
+and copying the required PGO runtime DLL to your build output directory.
+
+Options:
+  -OutputDir PATH    Target directory to copy DLL (default: build\bin\Release)
+  -Help              Show this help message
+
+Example:
+  .\fix-pgo-dll.ps1
+  .\fix-pgo-dll.ps1 -OutputDir "C:\MyBuild\bin"
+"@
+}
+
+function Write-Header {
+    param([string]$Message)
+    Write-Host "`n=================================================================" -ForegroundColor Cyan
+    Write-Host $Message -ForegroundColor Cyan
+    Write-Host "=================================================================`n" -ForegroundColor Cyan
+}
+
+function Write-Info {
+    param([string]$Message)
+    Write-Host "[INFO] $Message" -ForegroundColor Green
+}
+
+function Write-Warning {
+    param([string]$Message)
+    Write-Host "[WARNING] $Message" -ForegroundColor Yellow
+}
+
+function Write-Error-Custom {
+    param([string]$Message)
+    Write-Host "[ERROR] $Message" -ForegroundColor Red
+}
+
+if ($Help) {
+    Show-Usage
+    exit 0
+}
+
+Write-Header "PGO DLL Fixer for Citron"
+
+# Find Visual Studio installation
+$VSInstallPath = $null
+$VSWhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
+
+if (Test-Path $VSWhere) {
+    Write-Info "Searching for Visual Studio installations..."
+    $VSInstallPath = & $VSWhere -latest -property installationPath
+    if ($VSInstallPath) {
+        Write-Info "Found Visual Studio at: $VSInstallPath"
+    }
+} else {
+    Write-Warning "vswhere.exe not found. Trying common installation paths..."
+}
+
+# Common Visual Studio installation paths
+$CommonPaths = @(
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\Community",
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\Professional", 
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\Enterprise",
+    "${env:ProgramFiles(x86)}\Microsoft Visual Studio\2019\Community",
+    "${env:ProgramFiles(x86)}\Microsoft Visual Studio\2019\Professional",
+    "${env:ProgramFiles(x86)}\Microsoft Visual Studio\2019\Enterprise"
+)
+
+if (-not $VSInstallPath) {
+    foreach ($path in $CommonPaths) {
+        if (Test-Path $path) {
+            $VSInstallPath = $path
+            Write-Info "Found Visual Studio at: $VSInstallPath"
+            break
+        }
+    }
+}
+
+if (-not $VSInstallPath) {
+    Write-Error-Custom "Visual Studio installation not found!"
+    Write-Host "Please ensure Visual Studio 2019 or 2022 is installed with C++ support."
+    Write-Host "You can download it from: https://visualstudio.microsoft.com/downloads/"
+    exit 1
+}
+
+# Search for pgort140.dll
+Write-Info "Searching for pgort140.dll..."
+
+$DllPaths = @(
+    "$VSInstallPath\VC\Redist\MSVC\*\x64\Microsoft.VC*.CRT\pgort140.dll",
+    "$VSInstallPath\VC\Redist\MSVC\*\x86\Microsoft.VC*.CRT\pgort140.dll",
+    "$VSInstallPath\VC\Tools\MSVC\*\bin\Hostx64\x64\pgort140.dll",
+    "$VSInstallPath\VC\Tools\MSVC\*\bin\Hostx64\x86\pgort140.dll",
+    "$VSInstallPath\VC\Tools\MSVC\*\bin\Hostx86\x64\pgort140.dll",
+    "$VSInstallPath\VC\Tools\MSVC\*\bin\Hostx86\x86\pgort140.dll"
+)
+
+$FoundDll = $null
+foreach ($pattern in $DllPaths) {
+    $matches = Get-ChildItem -Path $pattern -ErrorAction SilentlyContinue
+    if ($matches) {
+        $FoundDll = $matches[0].FullName
+        Write-Info "Found pgort140.dll at: $FoundDll"
+        break
+    }
+}
+
+if (-not $FoundDll) {
+    Write-Error-Custom "pgort140.dll not found in Visual Studio installation!"
+    Write-Host "This usually means:"
+    Write-Host "1. Visual Studio was installed without PGO support"
+    Write-Host "2. You need to install the 'MSVC v143 - VS 2022 C++ x64/x86 build tools' component"
+    Write-Host "3. Try repairing your Visual Studio installation"
+    Write-Host ""
+    Write-Host "To fix this:"
+    Write-Host "1. Open Visual Studio Installer"
+    Write-Host "2. Click 'Modify' on your Visual Studio installation"
+    Write-Host "3. Go to 'Individual components' tab"
+    Write-Host "4. Search for 'PGO' and ensure it's checked"
+    Write-Host "5. Click 'Modify' to install the component"
+    exit 1
+}
+
+# Create output directory if it doesn't exist
+if (-not (Test-Path $OutputDir)) {
+    Write-Info "Creating output directory: $OutputDir"
+    New-Item -ItemType Directory -Force -Path $OutputDir | Out-Null
+}
+
+# Copy the DLL
+try {
+    Write-Info "Copying pgort140.dll to: $OutputDir"
+    Copy-Item -Path $FoundDll -Destination $OutputDir -Force
+    Write-Info "Successfully copied pgort140.dll!"
+    
+    # Verify the copy
+    $CopiedDll = Join-Path $OutputDir "pgort140.dll"
+    if (Test-Path $CopiedDll) {
+        Write-Info "Verification: pgort140.dll is now available in $OutputDir"
+        Write-Host ""
+        Write-Host "You can now run your PGO instrumented Citron build!"
+    } else {
+        Write-Error-Custom "Failed to copy pgort140.dll"
+        exit 1
+    }
+} catch {
+    Write-Error-Custom "Error copying pgort140.dll: $($_.Exception.Message)"
+    exit 1
+}
+
+Write-Header "PGO DLL Fix Complete!"
+Write-Info "The pgort140.dll has been copied to your build output directory."
+Write-Info "Your PGO instrumented Citron build should now run without the DLL error."
+Write-Host ""
+Write-Info "Next steps:"
+Write-Host "1. Run your PGO instrumented build"
+Write-Host "2. Play games to collect profile data"
+Write-Host "3. Rebuild with PGO USE stage for optimization"