add missing includes to fix build

example/audio_duplex.c

@@ -42,7 +42,7 @@
  */
 
 #include "btstack.h"
-
+#include <stdio.h>
 
 // uncomment to test start/stop of loopback / audio driver
 // #define TEST_START_STOP_INTERVAL 5000

example/mod_player.c

@@ -44,6 +44,7 @@
 #include "btstack.h"
 #include "hxcmod.h"
 #include "mods/mod.h"
+#include <stdio.h>
 
 static modcontext mod_context;
 

example/sine_player.c

@@ -43,6 +43,7 @@
  */
 
 #include "btstack.h"
+#include <stdio.h>
 
 #define TABLE_SIZE_441HZ            100
 

platform/embedded/btstack_uart_block_embedded.c

@@ -49,6 +49,9 @@
 #include "btstack_run_loop_embedded.h"
 #include "hal_uart_dma.h"
 
+// NULL
+#include <stddef.h>
+
 // uart config
 static const btstack_uart_config_t * btstack_uart_block_configuration;