Updated ALSA audio support for ALSA 0.9

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40355

configure.in

@@ -269,14 +269,25 @@ CheckALSA()
 [  --enable-alsa           support the ALSA audio API [default=yes]],
                   , enable_alsa=yes)
     if test x$enable_audio = xyes -a x$enable_alsa = xyes; then
+        AC_MSG_CHECKING(for ALSA audio support)
         have_alsa=no
-        AC_CHECK_HEADER(sys/asoundlib.h, have_alsa_hdr=yes)
-        AC_CHECK_LIB(asound, snd_pcm_open, have_alsa_lib=yes)
-        if test x$have_alsa_hdr = xyes -a x$have_alsa_lib = xyes; then
+        AC_TRY_COMPILE([
+          #include <alsa/asoundlib.h>
+        ],[
+          #if SND_LIB_VERSION < ((0<<16)|(9<<8)|0)
+          #error Your version of ALSA is too old
+          #endif
+          snd_pcm_t *pcm_handle;
+        ],[
+        AC_CHECK_LIB(asound, snd_pcm_open, have_alsa=yes)
+        ])
+        if test x$have_alsa = xyes; then
             CFLAGS="$CFLAGS -DALSA_SUPPORT"
             SYSTEM_LIBS="$SYSTEM_LIBS -lasound"
             AUDIO_SUBDIRS="$AUDIO_SUBDIRS alsa"
             AUDIO_DRIVERS="$AUDIO_DRIVERS alsa/libaudio_alsa.la"
+        else
+            AC_MSG_RESULT($have_alsa)
         fi
     fi
 }

src/audio/alsa/SDL_alsa_audio.h

@@ -24,38 +24,27 @@
 #define _ALSA_PCM_audio_h
 
 #include "SDL_sysaudio.h"
-#include <sys/asoundlib.h>
+#include <alsa/asoundlib.h>
 
 /* Hidden "this" pointer for the video functions */
 #define _THIS	SDL_AudioDevice *this
 
 struct SDL_PrivateAudioData {
 	/* The audio device handle */
-	 snd_pcm_t *audio_handle;
-
-	/* The audio file descriptor */
-	int audio_fd;
+	snd_pcm_t *pcm_handle;
 
 	/* The parent process id, to detect when application quits */
 	pid_t parent;
 
 	/* Raw mixing buffer */
-	Uint8 *pcm_buf;
-	int    pcm_len;
-
-	/* Support for audio timing using a timer, in addition to select() */
-	float frame_ticks;
-	float next_frame;
+	Uint8 *mixbuf;
+	int    mixlen;
 };
-#define FUDGE_TICKS	10	/* The scheduler overhead ticks per frame */
 
 /* Old variable names */
-#define audio_handle	(this->hidden->audio_handle)
-#define audio_fd		(this->hidden->audio_fd)
+#define pcm_handle		(this->hidden->pcm_handle)
 #define parent			(this->hidden->parent)
-#define pcm_buf			(this->hidden->pcm_buf)
-#define pcm_len			(this->hidden->pcm_len)
-#define frame_ticks		(this->hidden->frame_ticks)
-#define next_frame		(this->hidden->next_frame)
+#define mixbuf			(this->hidden->mixbuf)
+#define mixlen			(this->hidden->mixlen)
 
 #endif /* _ALSA_PCM_audio_h */

src/audio/dma/SDL_dmaaudio.c

@@ -377,6 +377,7 @@ static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec)
 				}
 				break;
 			default:
+				format = 0;
 				break;
 		}
 		if ( ! format ) {

src/audio/dsp/SDL_dspaudio.c

@@ -394,6 +394,7 @@ static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec)
 				}
 				break;
 			default:
+				format = 0;
 				break;
 		}
 		if ( ! format ) {