Ignore the DISPATCH_NOESCAPE if not defined

[kongyi]

Summary

This macro is only defined after XCode 8, causing build breakage for build systems with prior versions. Ignore DISPATCH_NOESCAPE if not defined.

[ahatanak]

Thanks for fixing this.

Can you make this simpler by defining DISPATCH_NOESCAPE only when it hasn't been defined?

#ifndef DISPATCH_NOESCAPE
#define DISPATCH_NOESCAPE
#endif

[kongyi]

In D41601#964657, @ahatanak wrote:

Thanks for fixing this.

Can you make this simpler by defining DISPATCH_NOESCAPE only when it hasn't been defined?

#ifndef DISPATCH_NOESCAPE
#define DISPATCH_NOESCAPE
#endif

Done

[ahatanak]

Looks good

compiler-rt/trunk/lib/tsan/rtl/tsan_libdispatch_mac.cc

 #include "tsan_interceptors.h"
 #include "tsan_platform.h"
 #include "tsan_rtl.h"
 
 #include <Block.h>
 #include <dispatch/dispatch.h>
 #include <pthread.h>
 
+// DISPATCH_NOESCAPE is not defined prior to XCode 8.
+#ifndef DISPATCH_NOESCAPE
+#define DISPATCH_NOESCAPE
+#endif
+
 typedef long long_t;  // NOLINT
 
 namespace __tsan {
 
 typedef struct {
   dispatch_queue_t queue;
   void *orig_context;
   dispatch_function_t orig_work;