template<class T, class Allocator, class U>
typename forward_list<T, Allocator>::size_type
erase(forward_list<T, Allocator>& c, const U& value);
template<class T, class Allocator, class Predicate>
typename forward_list<T, Allocator>::size_type
erase_if(forward_list<T, Allocator>& c, Predicate pred);