diff --git a/liba/include/stddef.h b/liba/include/stddef.h
index b041477e7..39c5b9b69 100644
--- a/liba/include/stddef.h
+++ b/liba/include/stddef.h
@@ -5,6 +5,7 @@
 
 typedef int ssize_t;
 typedef unsigned int size_t;
+typedef int ptrdiff_t;
 
 #define offsetof(type, field) __builtin_offsetof(type, field)