wasapi: Initial WASAPI support, for Windows Vista and later.

This should remain binary compatible with Windows XP, as we dynamically
load anything we need and fall back to DirectSound/WinMM/XAudio2 if not
available.

src/audio/wasapi/SDL_wasapi.h

@@ -0,0 +1,46 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2017 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_internal.h"
+
+#ifndef SDL_wasapi_h_
+#define SDL_wasapi_h_
+
+#include "../SDL_sysaudio.h"
+
+/* Hidden "this" pointer for the audio functions */
+#define _THIS SDL_AudioDevice *this
+
+struct SDL_PrivateAudioData
+{
+    IMMDevice *device;
+    WAVEFORMATEX *waveformat;
+    IAudioClient *client;
+    IAudioRenderClient *render;
+    IAudioCaptureClient *capture;
+    SDL_AudioStream *capturestream;
+    HANDLE task;
+    SDL_bool coinitialized;
+    int framesize;
+};
+
+#endif /* SDL_wasapi_h_ */
+
+/* vi: set ts=4 sw=4 expandtab: */