GLInterface: Destroy GLWin

Everything is now safely tucked inside each individual GLInterface.

Source/Core/DolphinWX/GLInterface/GLX.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <string>
+#include <GL/glx.h>
 
 #include "DolphinWX/GLInterface/X11_Util.h"
 #include "VideoBackends/OGL/GLInterfaceBase.h"
@@ -13,6 +14,10 @@ class cInterfaceGLX : public cInterfaceBase
 {
 private:
 	cX11Window XWindow;
+	Display *dpy;
+	Window win;
+	GLXContext ctx;
+	XVisualInfo *vi;
 public:
 	friend class cX11Window;
 	void SwapInterval(int Interval) override;