thirdparty: remove the atomic_thread_fence redefines for latest tcc on macos (not needed anymore)

Author: spytheman

thirdparty/stdatomic/nix/atomic.h

@@ -54,15 +54,17 @@ typedef volatile uintptr_t atomic_uintptr_t;
 extern void atomic_thread_fence (int memory_order);
 extern void __atomic_thread_fence (int memory_order);
 
-// workaround for tcc/aarch64
-#if defined(__aarch64__) || defined(_M_ARM64)
+// workaround for tcc/aarch64; Note: latest prebuilt tcc works, and does not need this hack:
+#if !defined(__APPLE__)
+#if (defined(__aarch64__) || defined(_M_ARM64))
     // `_V_atomic_thread_fence` is defined in `atomic.S`
     extern void _V_atomic_thread_fence(int memory_order);
     #define atomic_thread_fence(order) _V_atomic_thread_fence(order)
     #define __atomic_thread_fence(order) _V_atomic_thread_fence(order)
 #else
     #define atomic_thread_fence(order) __atomic_thread_fence(order)
 #endif
+#endif
 
 // use functions for 64, 32 and 8 bit from libatomic directly
 // since tcc is not capible to use "generic" C functions