Readd missing import files

Imports/Enviro - Sky and Weather/Enviro Standard/Scripts/Editor/EnviroAddDefineSymbolsHD.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Linq;
+using UnityEditor;
+
+[InitializeOnLoad]
+sealed class EnviroAddDefineSymbolsHD
+{
+    const string k_Define = "ENVIRO_HD";
+
+    static EnviroAddDefineSymbolsHD()
+    {
+        var targets = Enum.GetValues(typeof(BuildTargetGroup))
+            .Cast<BuildTargetGroup>()
+            .Where(x => x != BuildTargetGroup.Unknown)
+            .Where(x => !IsObsolete(x));
+
+        foreach (var target in targets)
+        {
+            var defines = PlayerSettings.GetScriptingDefineSymbolsForGroup(target).Trim();
+
+            var list = defines.Split(';', ' ')
+                .Where(x => !string.IsNullOrEmpty(x))
+                .ToList();
+
+            if (list.Contains(k_Define))
+                continue;
+
+            list.Add(k_Define);
+            defines = list.Aggregate((a, b) => a + ";" + b);
+
+            PlayerSettings.SetScriptingDefineSymbolsForGroup(target, defines);
+        }
+    }
+
+    static bool IsObsolete(BuildTargetGroup group)
+    {
+        var attrs = typeof(BuildTargetGroup)
+            .GetField(group.ToString())
+            .GetCustomAttributes(typeof(ObsoleteAttribute), false);
+
+        return attrs != null && attrs.Length > 0;
+    }
+}