diff --git a/test/backtrace_test.cpp b/test/backtrace_test.cpp
index 25dccb3..df291c9 100644
--- a/test/backtrace_test.cpp
+++ b/test/backtrace_test.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 #include <assert.h>
+#include <stddef.h>
 #include <unwind.h>
 
 extern "C" _Unwind_Reason_Code