Fix problems discovered with gcc 4.9.1

util/misc/initialization_state.h

Index: util/misc/initialization_state.h
diff --git a/util/misc/initialization_state.h b/util/misc/initialization_state.h
index b5a72031698e2b82048e300899877cfbc44b817c..b0496e5c131909733aa26ba9843d3a0feed5149c 100644
--- a/util/misc/initialization_state.h
+++ b/util/misc/initialization_state.h
@@ -86,7 +86,11 @@ class InitializationState {
   void set_state(State state) { state_ = state; }
 
  private:
-  State state_;
+  // state_ is volatile to ensure that it’ll be set by the destructor when it
+  // runs. Otherwise, optimizations might prevent it from ever being set to
+  // kStateDestroyed, limiting this class’ ability to catch use-after-free
+  // errors.
+  volatile State state_;
 
   DISALLOW_COPY_AND_ASSIGN(InitializationState);
 };