output: include cleanup

Don't include output_api.h in output_internal.h.  This change requires
adding missing includes in several sources.

src/audio.c

@@ -20,6 +20,7 @@
 #include "audio_format.h"
 #include "audio_parser.h"
 #include "output_internal.h"
+#include "output_plugin.h"
 #include "output_all.h"
 #include "mixer_api.h"
 

src/output_all.c

@@ -19,8 +19,10 @@
 #include "output_all.h"
 #include "output_internal.h"
 #include "output_control.h"
+#include "conf.h"
 
 #include <assert.h>
+#include <string.h>
 
 static struct audio_format input_audio_format;
 

src/output_internal.h

@@ -20,7 +20,7 @@
 #ifndef MPD_OUTPUT_INTERNAL_H
 #define MPD_OUTPUT_INTERNAL_H
 
-#include "output_api.h"
+#include "audio_format.h"
 #include "pcm_convert.h"
 #include "notify.h"
 

src/output_state.c

@@ -28,8 +28,8 @@
 #include <glib.h>
 
 #include <assert.h>
-#include <stdbool.h>
 #include <stdlib.h>
+#include <string.h>
 
 #define AUDIO_DEVICE_STATE "audio_device_state:"