Merge pull request #4103 from laytan/wait-shared-on-macos-10-15

UL_COMPARE_AND_WAIT_SHARED is macOS 10.15+

src/threading.cpp

@@ -839,8 +839,16 @@ gb_internal void futex_signal(Futex *f) {
 		}
 	} else {
 	#endif
+	// UL_COMPARE_AND_WAIT_SHARED is only available on macOS 10.15+
+	int WAIT_FLAG;
+	if (__builtin_available(macOS 10.15, *)) {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT_SHARED;
+	} else {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT;
+	}
+
 	for (;;) {
-		int ret = __ulock_wake(UL_COMPARE_AND_WAIT_SHARED | ULF_NO_ERRNO, f, 0);
+		int ret = __ulock_wake(WAIT_FLAG | ULF_NO_ERRNO, f, 0);
 		if (ret >= 0) {
 			return;
 		}
@@ -875,9 +883,17 @@ gb_internal void futex_broadcast(Futex *f) {
 		}
 	} else {
 	#endif
+	// UL_COMPARE_AND_WAIT_SHARED is only available on macOS 10.15+
+	int WAIT_FLAG;
+	if (__builtin_available(macOS 10.15, *)) {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT_SHARED;
+	} else {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT;
+	}
+
 	for (;;) {
 		enum { ULF_WAKE_ALL = 0x00000100 };
-		int ret = __ulock_wake(UL_COMPARE_AND_WAIT_SHARED | ULF_NO_ERRNO | ULF_WAKE_ALL, f, 0);
+		int ret = __ulock_wake(WAIT_FLAG | ULF_NO_ERRNO | ULF_WAKE_ALL, f, 0);
 		if (ret == 0) {
 			return;
 		}
@@ -915,8 +931,16 @@ gb_internal void futex_wait(Futex *f, Footex val) {
 		}
 	} else {
 	#endif
+	// UL_COMPARE_AND_WAIT_SHARED is only available on macOS 10.15+
+	int WAIT_FLAG;
+	if (__builtin_available(macOS 10.15, *)) {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT_SHARED;
+	} else {
+		WAIT_FLAG = UL_COMPARE_AND_WAIT;
+	}
+
 	for (;;) {
-		int ret = __ulock_wait(UL_COMPARE_AND_WAIT_SHARED | ULF_NO_ERRNO, f, val, 0);
+		int ret = __ulock_wait(WAIT_FLAG | ULF_NO_ERRNO, f, val, 0);
 		if (ret >= 0) {
 			if (*f != val) {
 				return;