Support XDG Desktop Portal as color picker provider

Wayland and XWayland fallback implementation uses XDP in
order to query picked color from desktop.

Source/Tools/Flax.Build/Deps/Dependencies/libportal.cs

@@ -0,0 +1,90 @@
+// Copyright (c) 2012-2024 Wojciech Figat. All rights reserved.
+
+using System.Collections.Generic;
+using System.IO;
+using Flax.Build;
+
+namespace Flax.Deps.Dependencies;
+
+/// <summary>
+/// libportal.
+/// </summary>
+/// <seealso cref="Flax.Deps.Dependency" />
+class libportal : Dependency
+{
+    /// <inheritdoc />
+    public override TargetPlatform[] Platforms
+    {
+        get
+        {
+            switch (BuildPlatform)
+            {
+            case TargetPlatform.Linux:
+                return new[]
+                {
+                    TargetPlatform.Linux,
+                };
+            default: return new TargetPlatform[0];
+            }
+        }
+    }
+
+    /// <inheritdoc />
+    public override void Build(BuildOptions options)
+    {
+        var dstPath = Path.Combine(options.ThirdPartyFolder, "libportal");
+        var includePath = Path.Combine(dstPath, "include");
+        
+        string root = options.IntermediateFolder;
+        var configs = new string[]
+        {
+            "-Dbackend-qt6=disabled",
+            "-Dbackend-qt5=disabled",
+            "-Dbackend-gtk4=disabled",
+            "-Dbackend-gtk3=disabled",
+            "-Dintrospection=false",
+            "-Dtests=false",
+            "-Ddocs=false",
+            "-Dvapi=false",
+            "--buildtype release",
+            "--default-library static",
+        };
+        
+        CloneGitRepo(root, "https://github.com/flatpak/libportal");
+        GitFetch(root);
+        GitResetToCommit(root, "8f5dc8d192f6e31dafe69e35219e3b707bde71ce");  // 0.9.1
+
+        foreach (var platform in options.Platforms)
+        {
+            BuildStarted(platform);
+            switch (platform)
+            {
+            case TargetPlatform.Linux:
+            {
+                foreach (var architecture in new TargetArchitecture[] { TargetArchitecture.x64 /*, TargetArchitecture.ARM64*/ })
+                {
+                    var buildDir = $"build_{architecture}";
+                    Utilities.Run("meson", $"{buildDir} {string.Join(" ", configs)}", null, root, Utilities.RunOptions.DefaultTool);
+                    Utilities.Run("ninja", $"-C {buildDir} ", null, root, Utilities.RunOptions.DefaultTool);
+
+                    var depsFolder = GetThirdPartyFolder(options, platform, architecture);
+                    Utilities.FileCopy(Path.Combine(root, buildDir, "libportal", "libportal.a"), Path.Combine(depsFolder, "libportal.a"));
+                    Utilities.FileCopy(Path.Combine(root, buildDir, "libportal", "portal-enums.h"), Path.Combine(includePath, "portal-enums.h"));
+                    Utilities.FileCopy(Path.Combine(root, buildDir, "libportal", "portal-enums.c"), Path.Combine(dstPath, "portal-enums.c"));
+                }
+                
+                Utilities.FileCopy(Path.Combine(root, "COPYING"), Path.Combine(dstPath, "LICENSE.txt"));
+                
+                if (!Directory.Exists(includePath))
+                    Directory.CreateDirectory(includePath);
+                if (!Directory.Exists(Path.Combine(includePath, "libportal")))
+                    Directory.CreateDirectory(Path.Combine(includePath, "libportal"));
+                
+                foreach (var file in Directory.GetFiles(Path.Combine(root, "libportal"), "*.h"))
+                    Utilities.FileCopy(file, Path.Combine(includePath, "libportal", Path.GetFileName(file)));
+                break;
+            }
+            }
+        }
+    }
+}

Source/Tools/Flax.Build/Platforms/Linux/LinuxToolchain.cs

@@ -126,7 +126,16 @@ namespace Flax.Build.Platforms
             args.Add("-lXcursor");
             args.Add("-lXinerama");
             args.Add("-lXfixes");
-            args.Add("-lwayland-client");
+
+            if (EngineConfiguration.WithSDL(options))
+            {
+                // Link Wayland
+                args.Add("-lwayland-client");
+
+                // Link GLib for libportal
+                args.Add("-lglib-2.0");
+                args.Add("-lgio-2.0");
+            }
         }
 
         /// <inheritdoc />