pcm: Fix segfault with 32bit libs

The recent rearrangement of header inclusion order caused a regression
showing segfaults on 32bit Arm.  The primary reason is the
inconsistent compile condition depending on the inclusion of config.h;
while most of other code include pcm_local.h (that implicitly includes
config.h) at first, pcm_direct.c doesn't do it, hence the access with
direct plugins crashes.

For fixing it, we need to include config.h at the beginning.  But,
it's better to include pcm_local.h for all relevant code for
consistency.  The patch does it, and also it adds the guard in
pcm_local.h for double inclusions.

Fixes: ad3a8b8b31 ("reshuffle included files to include config.h as first")
Link: https://github.com/alsa-project/alsa-lib/issues/352
Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/pcm/pcm_direct.c

@@ -19,6 +19,7 @@
  *
  */
   
+#include "pcm_local.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>

src/pcm/pcm_dmix.c

@@ -26,7 +26,7 @@
  *
  */
   
-#include "config.h"
+#include "pcm_local.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>

src/pcm/pcm_dshare.c

@@ -26,6 +26,7 @@
  *
  */
   
+#include "pcm_local.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>

src/pcm/pcm_dsnoop.c

@@ -26,6 +26,7 @@
  *
  */
   
+#include "pcm_local.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>

src/pcm/pcm_local.h

@@ -20,6 +20,9 @@
  *
  */
 
+#ifndef __PCM_LOCAL_H
+#define __PCM_LOCAL_H
+
 #include "config.h"
 
 #include <stdio.h>
@@ -1223,3 +1226,5 @@ static inline void snd_pcm_unlock(snd_pcm_t *pcm)
 #define snd_pcm_lock(pcm)		do {} while (0)
 #define snd_pcm_unlock(pcm)		do {} while (0)
 #endif /* THREAD_SAFE_API */
+
+#endif /* __PCM_LOCAL_H */

src/pcm/pcm_shm.c

@@ -26,6 +26,7 @@
  *
  */
   
+#include "pcm_local.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>