Revert "[TSan] Don't guard #include <xpc/xpc.h>"

This reverts commit 8191585b36eb4963002cce43fb2e79e7fb05c3d6.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@369165 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/tsan/rtl/tsan_interceptors_mac.cpp b/lib/tsan/rtl/tsan_interceptors_mac.cpp
index 7b91736..db73927 100644
--- a/lib/tsan/rtl/tsan_interceptors_mac.cpp
+++ b/lib/tsan/rtl/tsan_interceptors_mac.cpp
@@ -24,7 +24,10 @@
 #include <libkern/OSAtomic.h>
 #include <objc/objc-sync.h>
 #include <sys/ucontext.h>
+
+#if defined(__has_include) && __has_include(<xpc/xpc.h>)
 #include <xpc/xpc.h>
+#endif  // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
 
 typedef long long_t;  // NOLINT
 
@@ -296,6 +299,8 @@
   REAL(os_unfair_lock_unlock)(lock);
 }
 
+#if defined(__has_include) && __has_include(<xpc/xpc.h>)
+
 TSAN_INTERCEPTOR(void, xpc_connection_set_event_handler,
                  xpc_connection_t connection, xpc_handler_t handler) {
   SCOPED_TSAN_INTERCEPTOR(xpc_connection_set_event_handler, connection,
@@ -348,6 +353,8 @@
   REAL(xpc_connection_cancel)(connection);
 }
 
+#endif  // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
+
 // Determines whether the Obj-C object pointer is a tagged pointer. Tagged
 // pointers encode the object data directly in their pointer bits and do not
 // have an associated memory allocation. The Obj-C runtime uses tagged pointers