generate glenum, link glenum, add source gen for text regex

tools/StgSharp.GenerateGL/Generation/GlGenerationTarget.cs

@@ -0,0 +1,20 @@
+// -----------------------------------------------------------------------------
+// file="GlGenerationTarget"
+// Project: StgSharp
+// Copyright (c) Nitload.
+// SPDX-License-Identifier: MIT
+// -----------------------------------------------------------------------------
+
+using System;
+
+namespace StgSharp.GenerateGL.Generation
+{
+    [Flags]
+    internal enum GlGenerationTarget
+    {
+        None = 0,
+        Api = 1,
+        Enum = 2,
+        All = Api | Enum,
+    }
+}