build: remove entt library

include/entt/stl/concepts.hpp

@@ -1,24 +0,0 @@
-#ifndef ENTT_STL_CONCEPTS_HPP
-#define ENTT_STL_CONCEPTS_HPP
-
-/*! @cond ENTT_INTERNAL */
-#if __has_include(<entt/ext/stl/concepts.hpp>)
-#    include <entt/ext/stl/concepts.hpp>
-#else
-#    include <concepts>
-
-namespace entt::stl {
-
-using std::constructible_from;
-using std::default_initializable;
-using std::derived_from;
-using std::integral;
-using std::invocable;
-using std::same_as;
-using std::unsigned_integral;
-
-} // namespace entt::stl
-#endif
-/*! @endcond */
-
-#endif