+#define must_inline __attribute__((always_inline))
+#define must_emit __attribute__((used))
+#define unreachable __builtin_unreachable()
+
+#define clz(bits) __builtin_clz(bits)
+#define sadd_overflow(a, b, of) __builtin_sadd_overflow(a, b, of)
+#define umul_overflow(a, b, of) __builtin_umul_overflow(a, b, of)
+#define offsetof(f, m) __builtin_offsetof(f, m)