Use stdatomic.h on recent macOS

Author: nobu

ext/concurrent-ruby-ext/atomic_reference.c

@@ -78,7 +78,11 @@ VALUE ir_get_and_set(VALUE self, VALUE new_value) {
 }
 
 VALUE ir_compare_and_set(volatile VALUE self, VALUE expect_value, VALUE new_value) {
-#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101200
+  if (atomic_compare_exchange_strong_explicit((_Atomic uintptr_t *)&DATA_PTR(self), &expect_value, new_value, memory_order_seq_cst, memory_order_seq_cst)) {
+    return Qtrue;
+  }
+#elif defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
   if (OSAtomicCompareAndSwap64(expect_value, new_value, &DATA_PTR(self))) {
     return Qtrue;
   }

ext/concurrent-ruby-ext/atomic_reference.h

@@ -5,6 +5,9 @@
 #include <atomic.h>
 #endif
 
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101200
+#include <stdatomic.h>
+#endif
 #ifdef HAVE_LIBKERN_OSATOMIC_H
 #include <libkern/OSAtomic.h>
 #endif