[X11] Reconcile logical keyboard state with physical state on FocusIn

since the window system doesn't do it for us like other platforms.

This prevents sticky keys and missed keys when going in and out
of focus, for example Alt would appear to stick if switching away
from an SDL app with Alt-Tab and had to be pressed again.

CR: Sam

include/SDL_opengles2_gl2platform.h

@@ -0,0 +1,30 @@
+#ifndef __gl2platform_h_
+#define __gl2platform_h_
+
+/* $Revision: 10602 $ on $Date:: 2010-03-04 22:35:34 -0800 #$ */
+
+/*
+ * This document is licensed under the SGI Free Software B License Version
+ * 2.0. For details, see http://oss.sgi.com/projects/FreeB/ .
+ */
+
+/* Platform-specific types and definitions for OpenGL ES 2.X  gl2.h
+ *
+ * Adopters may modify khrplatform.h and this file to suit their platform.
+ * You are encouraged to submit all modifications to the Khronos group so that
+ * they can be included in future versions of this file.  Please submit changes
+ * by sending them to the public Khronos Bugzilla (http://khronos.org/bugzilla)
+ * by filing a bug against product "OpenGL-ES" component "Registry".
+ */
+
+/*#include <KHR/khrplatform.h>*/
+
+#ifndef GL_APICALL
+#define GL_APICALL  KHRONOS_APICALL
+#endif
+
+#ifndef GL_APIENTRY
+#define GL_APIENTRY KHRONOS_APIENTRY
+#endif
+
+#endif /* __gl2platform_h_ */