diff --git a/lib/builtins/gcc_personality_v0.c b/lib/builtins/gcc_personality_v0.c
index 9fb1ce0..cecbce1 100644
--- a/lib/builtins/gcc_personality_v0.c
+++ b/lib/builtins/gcc_personality_v0.c
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "int_lib.h"
+#include <stddef.h>
 
 #include <unwind.h>
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) &&                          \