diff --git a/src/lib/stddef.h b/src/lib/stddef.h
new file mode 100644
index 0000000000000000000000000000000000000000..4e74fa6178e80b155a776b77b2c90d3d9e7d1b4b
--- /dev/null
+++ b/src/lib/stddef.h
@@ -0,0 +1,12 @@
+#ifndef __LIB_STDDEF_H
+#define __LIB_STDDEF_H
+
+#define NULL ((void *) 0)
+#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *) 0)->MEMBER)
+
+/* GCC predefines the types we need for ptrdiff_t and size_t,
+   so that we don't have to guess. */
+typedef __PTRDIFF_TYPE__ ptrdiff_t;
+typedef __SIZE_TYPE__ size_t;
+
+#endif /* lib/stddef.h */