Codechange: Suppress warnings when asserts are disabled (#8916)

src/blitter/factory.hpp

@@ -61,13 +61,14 @@ protected:
 			name(name), description(description)
 	{
 		if (usable) {
+			Blitters &blitters = GetBlitters();
+			assert(blitters.find(this->name) == blitters.end());
 			/*
 			 * Only add when the blitter is usable. Do not bail out or
 			 * do more special things since the blitters are always
 			 * instantiated upon start anyhow and freed upon shutdown.
 			 */
-			std::pair<Blitters::iterator, bool> P = GetBlitters().insert(Blitters::value_type(this->name, this));
-			assert(P.second);
+			blitters.insert(Blitters::value_type(this->name, this));
 		} else {
 			DEBUG(driver, 1, "Not registering blitter %s as it is not usable", name);
 		}