Ensures deterministic initial state for the atomic flag.

Concurrency/BestEffortUpdater.cpp

@@ -12,6 +12,11 @@
 
 using namespace Concurrency;
 
+BestEffortUpdater::BestEffortUpdater() {
+	// ATOMIC_FLAG_INIT isn't necessarily safe to use, so establish default state by other means.
+	update_is_ongoing_.clear();
+}
+
 void BestEffortUpdater::update() {
 	// Perform an update only if one is not currently ongoing.
 	if(!update_is_ongoing_.test_and_set()) {

Concurrency/BestEffortUpdater.hpp

@@ -25,6 +25,8 @@ namespace Concurrency {
 */
 class BestEffortUpdater {
 	public:
+		BestEffortUpdater();
+
 		/// A delegate receives timing cues.
 		struct Delegate {
 			virtual void update(BestEffortUpdater *updater, int cycles, bool did_skip_previous_update) = 0;