Added native OpenBSD audio driver (thanks vedge!)

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%4038

src/audio/openbsd/SDL_openbsdaudio.h

@@ -0,0 +1,57 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifndef _SDL_openbsdaudio_h
+#define _SDL_openbsdaudio_h
+
+#include "SDL_sysaudio.h"
+
+#define _THIS	SDL_AudioDevice *this
+
+struct SDL_PrivateAudioData
+{
+    /* The file descriptor for the audio device */
+    int audio_fd;
+
+    /* The parent process id, to detect when application quits */
+    pid_t parent;
+
+    /* Raw mixing buffer */
+    Uint8 *mixbuf;
+    int    mixlen;
+
+    /* Support for audio timing using a timer, in addition to select() */
+    float frame_ticks;
+    float next_frame;
+};
+
+#define FUDGE_TICKS	10	/* The scheduler overhead ticks per frame */
+
+/* Old variable names */
+#define audio_fd		(this->hidden->audio_fd)
+#define parent			(this->hidden->parent)
+#define mixbuf			(this->hidden->mixbuf)
+#define mixlen			(this->hidden->mixlen)
+#define frame_ticks		(this->hidden->frame_ticks)
+#define next_frame		(this->hidden->next_frame)
+
+#endif /* _SDL_openbsdaudio_h */