diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 0eb0e0a..316a14a 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -30,6 +30,7 @@
 
 #include <pthread.h>
 #include <stdbool.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS