apps: common: event_loop: Use std::deque instead of std::list

Deque has fast pop_front and push_back operations while making
fewer allocations for the same number of elements as an `std::list`.
So use an `std::deque` for storing the deferred calls of the loop.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/apps/common/event_loop.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <chrono>
+#include <deque>
 #include <functional>
 #include <list>
 #include <memory>
@@ -63,7 +64,8 @@ private:
 	struct event_base *base_;
 	int exitCode_;
 
-	std::list<std::function<void()>> calls_;
+	std::deque<std::function<void()>> calls_;
+
 	std::list<std::unique_ptr<Event>> events_;
 	std::mutex lock_;