Subzero: Make thread_local work under MacOS 10.6.

src/IceGlobalContext.h

 //===- subzero/src/IceGlobalContext.h - Global context defs -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares aspects of the compilation that persist across
@@ skipping 256 matching lines @@
   LockedPtr<CodeStats> getStatsCumulative() {
     return LockedPtr<CodeStats>(&StatsCumulative, &StatsLock);
   }
   LockedPtr<std::vector<TimerStack>> getTimers() {
     return LockedPtr<std::vector<TimerStack>>(&Timers, &TimerLock);
   }
 
   std::vector<ThreadContext *> AllThreadContexts;
   // Each thread has its own TLS pointer which is also held in
   // AllThreadContexts.
-  thread_local static ThreadContext *TLS;
+  ICE_ATTRIBUTE_TLS static ThreadContext *TLS;
 
   // Private helpers for mangleName()
   typedef llvm::SmallVector<char, 32> ManglerVector;
   void incrementSubstitutions(ManglerVector &OldName) const;
 };
 
 // Helper class to push and pop a timer marker.  The constructor
 // pushes a marker, and the destructor pops it.  This is for
 // convenient timing of regions of code.
 class TimerMarker {
@@ skipping 34 matching lines @@
   explicit OstreamLocker(GlobalContext *Ctx) : Ctx(Ctx) { Ctx->lockStr(); }
   ~OstreamLocker() { Ctx->unlockStr(); }
 
 private:
   GlobalContext *const Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEGLOBALCONTEXT_H