diff --git a/ac3dec/output.c b/ac3dec/output.c
index 142f675..957e0af 100644
--- a/ac3dec/output.c
+++ b/ac3dec/output.c
@@ -20,6 +20,10 @@
 
 #include <stdio.h>
 #include <errno.h>
+#include <assert.h>
+#include <alloca.h>
+#include <string.h>
+#include <unistd.h>
 #define ALSA_PCM_NEW_HW_PARAMS_API
 #define ALSA_PCM_NEW_SW_PARAMS_API
 #include <alsa/asoundlib.h>