Add glwindow.h for Windows

This file was taken from ioQuake2 and altered to work with Yamagi Quake
II

src/windows/header/glwindow.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 1997-2001 Id Software, Inc.
+ *
+ * This program 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 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * =======================================================================
+ *
+ * This file holds the main struct for the OpenGL context
+ *
+ * =======================================================================
+ */ 
+
+#ifndef __GLW_WIN_H__
+#define __GLW_WIN_H__
+
+typedef struct
+{
+	HINSTANCE hInstance;
+	void *wndproc;
+
+	HDC hDC;                /* handle to device context */
+	HWND hWnd;              /* handle to window */
+	HGLRC hGLRC;            /* handle to GL rendering context */
+
+	HINSTANCE hinstOpenGL;  /* HINSTANCE for the OpenGL library */
+
+	qboolean minidriver;
+	qboolean allowdisplaydepthchange;
+	qboolean mcd_accelerated;
+
+	FILE *log_fp;
+} glwstate_t;
+
+extern glwstate_t glw_state;
+
+#endif