diff --git a/libavutil/log.c b/libavutil/log.c
index 5e841296bb..e4a9fec552 100644
--- a/libavutil/log.c
+++ b/libavutil/log.c
@@ -24,7 +24,11 @@
  * logging functions
  */
 
+#include "config.h"
+
+#if HAVE_ISATTY
 #include <unistd.h>
+#endif
 #include <stdlib.h>
 #include "avstring.h"
 #include "avutil.h"