PUP: Fix support for STL containers with custom comparators (#3458)

Author: evan-charmworks

src/util/pup_stl.h

@@ -161,23 +161,23 @@ namespace PUP {
   {
     c.clear();
   }
-  template <class dtype>
-  inline void reserve_if_applicable(std::set<dtype> &c, size_t nElem)
+  template <class dtype, class cmp>
+  inline void reserve_if_applicable(std::set<dtype, cmp> &c, size_t nElem)
   {
     c.clear();
   }
-  template <class dtype>
-  inline void reserve_if_applicable(std::multiset<dtype> &c, size_t nElem)
+  template <class dtype, class cmp>
+  inline void reserve_if_applicable(std::multiset<dtype, cmp> &c, size_t nElem)
   {
     c.clear();
   }
-  template <class K, class V>
-  inline void reserve_if_applicable(std::map<K, V> &c, size_t nElem)
+  template <class K, class V, class cmp>
+  inline void reserve_if_applicable(std::map<K, V, cmp> &c, size_t nElem)
   {
     c.clear();
   }
-  template <class K, class V>
-  inline void reserve_if_applicable(std::multimap<K, V> &c, size_t nElem)
+  template <class K, class V, class cmp>
+  inline void reserve_if_applicable(std::multimap<K, V, cmp> &c, size_t nElem)
   {
     c.clear();
   }