diff --git a/libc/bionic/bionic_systrace.cpp b/libc/bionic/bionic_systrace.cpp
index f5be415..c74a52c 100644
--- a/libc/bionic/bionic_systrace.cpp
+++ b/libc/bionic/bionic_systrace.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <cutils/trace.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>