Make Engine_updateExpander() non-locking.

src/engine/Engine.cpp

@@ -289,13 +289,13 @@ struct Engine::Internal {
 };
 
 
-static void Engine_updateExpander(Engine* that, Module* module, bool side) {
+static void Engine_updateExpander_NoLock(Engine* that, Module* module, bool side) {
 	Module::Expander& expander = side ? module->rightExpander : module->leftExpander;
 	Module* oldExpanderModule = expander.module;
 
 	if (expander.moduleId >= 0) {
 		if (!expander.module || expander.module->id != expander.moduleId) {
-			expander.module = that->getModule(expander.moduleId);
+			expander.module = that->getModule_NoLock(expander.moduleId);
 		}
 	}
 	else {
@@ -592,8 +592,8 @@ void Engine::stepBlock(int frames) {
 
 	// Update expander pointers
 	for (Module* module : internal->modules) {
-		Engine_updateExpander(this, module, false);
-		Engine_updateExpander(this, module, true);
+		Engine_updateExpander_NoLock(this, module, false);
+		Engine_updateExpander_NoLock(this, module, true);
 	}
 
 	// Launch workers