CActorContraption fixes, better CMake dependency handling

Runtime/rstl.hpp

@@ -4,7 +4,7 @@
 #include <algorithm>
 #include <type_traits>
 #include <cstdlib>
-#include "optional.hpp"
+#include <optional>
 #include "logvisor/logvisor.hpp"
 
 namespace rstl {
@@ -658,9 +658,4 @@ string string_l(const char* data)
 }
 #endif
 
-template <class T>
-using optional = std::experimental::optional<T>;
-using nullopt_t = std::experimental::nullopt_t;
-constexpr nullopt_t nullopt{nullopt_t::init()};
-
 } // namespace rstl