Added version based define for availability of constant in internal module code. Added conditional compilation of how constant is defined.

Author: ekcoh

Packages/com.unity.inputsystem/InputSystem/Events/InputEvent.cs

@@ -65,7 +65,20 @@ public struct InputEvent
         /// </summary>
         public const int InvalidEventId = 0;
 
+        #if UNITY_INPUT_SYSTEM_INPUT_MODULE_DEFINES_EVENT_PACKING_ALIGNMENT
+        /// <summary>
+        /// Defines the packing alignment of native input events in event buffers.
+        /// </summary>
+        /// <remarks>
+        /// This is dictated by the native module implementation which populates the event buffers.
+        /// </remarks>
+        internal const int kAlignment = NativeInputEvent.alignment;
+        #else
+        /// <summary>
+        /// Defines the packing alignment of native input events in event buffers.
+        /// </summary>
         internal const int kAlignment = 4;
+        #endif
 
         [FieldOffset(0)]
         private NativeInputEvent m_Event;

Packages/com.unity.inputsystem/InputSystem/Unity.InputSystem.asmdef

@@ -111,6 +111,11 @@
             "name": "com.unity.modules.unityanalytics",
             "expression": "1",
             "define": "UNITY_INPUT_SYSTEM_ENABLE_ANALYTICS"
+        },
+        {
+            "name": "Unity",
+            "expression": "6000.2.0a11",
+            "define": "UNITY_INPUT_SYSTEM_INPUT_MODULE_DEFINES_EVENT_PACKING_ALIGNMENT"
         }
     ],
     "noEngineReferences": false