Add Polymorphic Memory Resource utilities and rework the separately compiled library:

- Dlmalloc's based C function are boost_cont_xxx no longer exported, but wrapped into C++ linkage dlmalloc_xxx functions to effectively reuse Boost's dynamic library and autolink machinery instead of rewriting machinery to compile the C source file.
- Refactored scoped_allocator_adaptor's construct logic as it was shared with polymorphic allocator's one. Moved common logic to detail/dispatch_uses_allocator.hpp. Refactored also scoped_allocator_adaptor test utilities to be reused with polymorphic_allocator tests.

src/global_resource.cpp

@@ -0,0 +1,106 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying file
+// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/container for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#define BOOST_CONTAINER_SOURCE
+#include <boost/container/pmr/memory_resource.hpp>
+
+#include <boost/core/no_exceptions_support.hpp>
+#include <boost/container/throw_exception.hpp>
+#include <boost/container/detail/dlmalloc.hpp>  //For global lock
+
+#include <cstddef>
+#include <new>
+
+namespace boost {
+namespace container {
+namespace pmr {
+
+class new_delete_resource_imp
+   : public memory_resource
+{
+   public:
+
+   virtual ~new_delete_resource_imp()
+   {}
+
+   virtual void* do_allocate(std::size_t bytes, std::size_t alignment)
+   {  return new char[bytes]; (void)bytes; (void)alignment;  }
+
+   virtual void do_deallocate(void* p, std::size_t bytes, std::size_t alignment)
+   {  delete[]((char*)p);  (void)bytes; (void)alignment;  }
+
+   virtual bool do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT
+   {  return &other == this;   }
+} new_delete_resource_instance;
+
+struct null_memory_resource_imp
+   : public memory_resource
+{
+   public:
+
+   virtual ~null_memory_resource_imp()
+   {}
+
+   virtual void* do_allocate(std::size_t bytes, std::size_t alignment)
+   {
+      (void)bytes; (void)alignment;
+      throw_bad_alloc();
+      return 0;
+   }
+
+   virtual void do_deallocate(void* p, std::size_t bytes, std::size_t alignment)
+   {  (void)p;  (void)bytes; (void)alignment;  }
+
+   virtual bool do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT
+   {  return &other == this;   }
+} null_memory_resource_instance;
+
+BOOST_CONTAINER_DECL memory_resource* new_delete_resource() BOOST_NOEXCEPT
+{
+   return &new_delete_resource_instance;
+}
+
+BOOST_CONTAINER_DECL memory_resource* null_memory_resource() BOOST_NOEXCEPT
+{
+   return &null_memory_resource_instance;
+}
+
+static memory_resource *default_memory_resource = &new_delete_resource_instance;
+
+BOOST_CONTAINER_DECL memory_resource* set_default_resource(memory_resource* r) BOOST_NOEXCEPT
+{
+   //TO-DO: synchronizes-with part using atomics
+   if(dlmalloc_global_sync_lock()){
+      memory_resource *previous = default_memory_resource;
+      default_memory_resource = r ? r : new_delete_resource();
+      dlmalloc_global_sync_unlock();
+      return previous;
+   }
+   else{
+      return new_delete_resource();
+   }
+}
+
+BOOST_CONTAINER_DECL memory_resource* get_default_resource() BOOST_NOEXCEPT
+{
+   //TO-DO: synchronizes-with part using atomics
+   if(dlmalloc_global_sync_lock()){
+      memory_resource *current = default_memory_resource;
+      dlmalloc_global_sync_unlock();
+      return current;
+   }
+   else{
+      return new_delete_resource();
+   }
+}
+
+}  //namespace pmr {
+}  //namespace container {
+}  //namespace boost {