[TSAN][Darwin] Forward declare spinlock functions on darwin for TSAN interceptors

[thetruestblue]

Summary

Spinlock symbols are removed from headers in MacOS version 10.12 and greater.
Even though they are deprecated, the symbols remain available on the system.

The TSAN interceptors currently cause a build failure after this version because
of the change in availability of the symbol.

We want to continue intercepting the symbols available on the OS.
So we add forward declarations so that the TSAN interceptors can build.

This is tested with the existing osspinlock_norace test.

[thetruestblue]

fixed trailing white space issues.

[yln]

LGTM, thanks!

compiler-rt/lib/tsan/rtl/tsan_interceptors_mac.cpp

 #include "tsan_interceptors.h"
 #include "tsan_interface.h"
 #include "tsan_interface_ann.h"
+#include "tsan_spinlock_defs_mac.h"
 #include "sanitizer_common/sanitizer_addrhashmap.h"
 
 #include <errno.h>

compiler-rt/lib/tsan/rtl/tsan_spinlock_defs_mac.h

+//===-- tsan_spinlock_defs_mac.h -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of ThreadSanitizer (TSan), a race detector.
+//
+// Mac-specific forward-declared function defintions that may be
+// deprecated in later versions of the OS.
+// These are needed for interceptors.
+//
+//===----------------------------------------------------------------------===//
+
+#if SANITIZER_APPLE
+
+#ifndef TSAN_SPINLOCK_DEFS_MAC_H
+#define TSAN_SPINLOCK_DEFS_MAC_H
+
+#include <stdint.h>
+
+extern "C" {
+
+/*
+Provides forward declarations related to OSSpinLocks on Darwin. These functions are
+deprecated on macOS version 10.12 and later,
+and are no longer included in the system headers.
+
+However, the symbols are still available on the system, so we provide these forward
+declarations to prevent compilation errors in tsan_interceptors_mac.cpp, which
+references these functions when defining TSAN interceptor functions.
+*/
+
+typedef int32_t OSSpinLock;
+
+void OSSpinLockLock(volatile OSSpinLock *__lock);
+void OSSpinLockUnlock(volatile OSSpinLock *__lock);
+bool OSSpinLockTry(volatile OSSpinLock *__lock);
+
+}
+
+#endif //TSAN_SPINLOCK_DEFS_MAC_H
+#endif // SANITIZER_APPLE