Fix defines.

Author: surfnerd

com.unity.ml-agents/Runtime/MLAgentsDefines.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 using System;
 using System.Collections.Generic;
 using UnityEngine;

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensor.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 #if MLA_UNITY_PHYSICS2D_MODULE_ENABLED
 using UnityEngine;
 

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensorComponent2D.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 #if MLA_UNITY_PHYSICS_MODULE_ENABLED
 using UnityEngine;
 using UnityEngine.Serialization;

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensorComponent3D.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 using System;
 using System.Collections.Generic;
 using UnityEngine;

com.unity.ml-agents/Runtime/Sensors/RayPerceptionSensorComponentBase.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 using System.Collections.Generic;
 using Unity.MLAgents.Sensors;
 using NUnit.Framework;

com.unity.ml-agents/Tests/Editor/PublicAPI/PublicApiValidation.cs

@@ -1,3 +1,11 @@
+#if MLA_UNITY_PHYSICS_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS_MODULE_ENABLED
+#endif
+
+#if MLA_UNITY_PHYSICS2D_MODULE || !UNITY_2019_4_OR_NEWER
+#define MLA_UNITY_PHYSICS2D_MODULE_ENABLED
+#endif
+
 using System;
 using System.Collections.Generic;
 using NUnit.Framework;