Bug 967926 - Make hasUncompiledCallTarget_ Atomic to be extra careful. (r=jandem)

js/src/jit/IonCode.h

@@ -196,7 +196,7 @@ struct IonScript
     // Flag set when it is likely that one of our (transitive) call
     // targets is not compiled.  Used in ForkJoin.cpp to decide when
     // we should add call targets to the worklist.
-    bool hasUncompiledCallTarget_;
+    mozilla::Atomic<bool, mozilla::Relaxed> hasUncompiledCallTarget_;
 
     // Flag set if IonScript was compiled with SPS profiling enabled.
     bool hasSPSInstrumentation_;