Dynamically check if DTrackPlugin is actually there.

RWTHVRToolkit.uplugin

@@ -47,18 +47,15 @@
 	"Plugins": [
 		{
 			"Name": "nDisplay",
-			"Enabled": true,
-			"Optional": true
+			"Enabled": true
 		},
 		{
 			"Name": "LiveLink",
-			"Enabled": true,
-			"Optional": true
+			"Enabled": true
 		},
 		{
 			"Name": "LiveLinkOvernDisplay",
-			"Enabled": true,
-			"Optional": true
+			"Enabled": true
 		},
 		{
 			"Name": "DTrackPlugin",

Source/RWTHVRCluster/RWTHVRCluster.Build.cs

@@ -20,17 +20,35 @@ public class RWTHVRCluster : ModuleRules
 				"Core",
 				"CoreUObject",
 				"Engine",
-			"RWTHVRToolkit",
-			"DisplayCluster",
 				"DeveloperSettings",
 				"InputCore",
 				"UMG",
 				"Slate",
 				"SlateCore",
+				"RWTHVRToolkit"
+			}
+		);
+
+		if (IsPluginEnabledForTarget("nDisplay", base.Target))
+		{
+			PublicDependencyModuleNames.AddRange(
+				new string[]
+				{
+					"DisplayCluster"
+				}
+			);
+		}
+		
+		if (IsPluginEnabledForTarget("DTrackPlugin", base.Target))
+		{
+			PublicDependencyModuleNames.AddRange(
+				new string[]
+				{
 					"DTrackPlugin",
 					"DTrackInput"
 				}
 			);
+		}
 
 		PrivateDependencyModuleNames.AddRange(
 			new string[]{}
@@ -40,4 +58,11 @@ public class RWTHVRCluster : ModuleRules
 			new string[] { }
 		);
 	}
+
+	private static bool IsPluginEnabledForTarget(string PluginName, ReadOnlyTargetRules Target)
+	{
+		var PL = Plugins.GetPlugin(PluginName);
+		return PL != null && Target.ProjectFile != null && Plugins.IsPluginEnabledForTarget(PL,
+			ProjectDescriptor.FromFile(Target.ProjectFile), Target.Platform, Target.Configuration, Target.Type);
+	}
 }