[SDL] Add global helper to setup the library.

Call to SDLHelper::Prepare() is needed before first SDL_InitSubSystem().
- Sets hints (SDL configuration vars).
- Configures logging.

src/xenia/helper/sdl/sdl_helper.h

@@ -0,0 +1,38 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2020 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_HELPER_SDL_SDL_HELPER_H_
+#define XENIA_HELPER_SDL_SDL_HELPER_H_
+
+#include "SDL.h"
+
+namespace xe {
+namespace helper {
+namespace sdl {
+// This helper class exists to independently use SDL from different parts of
+// xenia.
+class SDLHelper {
+ public:
+  // To configure the SDL library for use in xenia call this function before
+  // SDL_InitSubSystem() is called.
+  static bool Prepare();
+  static bool IsPrepared() { return is_prepared_; }
+
+ private:
+  static bool SetHints();
+  static bool RedirectLog();
+
+ private:
+  static bool is_prepared_;
+};
+}  // namespace sdl
+}  // namespace helper
+}  // namespace xe
+
+#endif  // XENIA_HELPER_SDL_SDL_HELPER_H_