WinRT: added missing files

src/core/winrt/SDL_winrtapp_common.cpp

@@ -0,0 +1,16 @@
+
+#include <SDL_system.h>
+#include "SDL_winrtapp_direct3d.h"
+#include "SDL_winrtapp_xaml.h"
+
+int (*WINRT_SDLAppEntryPoint)(int, char **) = NULL;
+
+extern "C" DECLSPEC int
+SDL_WinRTRunApp(int (*mainFunction)(int, char **), void * xamlBackgroundPanel)
+{
+    if (xamlBackgroundPanel) {
+        return SDL_WinRTInitXAMLApp(mainFunction, xamlBackgroundPanel);
+    } else {
+        return SDL_WinRTInitNonXAMLApp(mainFunction);
+    }
+}

src/core/winrt/SDL_winrtapp_common.h

@@ -0,0 +1,31 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifndef _SDL_winrtapp_common_h
+#define _SDL_winrtapp_common_h
+
+/* A pointer to the app's C-style main() function (which is a different
+   function than the WinRT app's actual entry point).
+ */
+extern int (*WINRT_SDLAppEntryPoint)(int, char **);
+
+#endif // ifndef _SDL_winrtapp_common_h