Added license.

neo/engine/opengl/DirectInputShim.cpp

@@ -1,3 +1,29 @@
+/*
+===========================================================================
+
+IceTech GPL Source Code
+Copyright (C) 2026 Justin Marshall
+
+This file is part of the IceTech GPL Source Code (?IceTech Source Code?).
+
+IceTech Source Code is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+IceTech Source Code is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with IceTech Source Code.  If not, see <http://www.gnu.org/licenses/>.
+
+If you have questions concerning this license or the applicable additional terms, you may contact in writing Justin Marshall, justinmarshall20@gmail.com
+
+===========================================================================
+*/
+
 #ifndef DIRECTINPUT_VERSION
 #define DIRECTINPUT_VERSION 0x0800
 #endif