try to fix macos 12 build
MODIFY
ir/fast_math.cpp
ir/fast_math.cpp
#include "ir/fast_math.h"
#include "ir/attrs.h"
+#include "util/spaceship.h"
#include "util/unionfind.h"
#include <map>
#include <vector>

MODIFY
util/spaceship.h
util/spaceship.h
#include <compare>
+#ifdef __APPLE__
+namespace std {
+inline bool is_neq(std::weak_ordering o) { return o != 0; }
+}
+#endif
+
namespace {
inline

try to fix macos 12 build