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.

test/derived_from_memory_resource.hpp

@@ -0,0 +1,87 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// (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.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_CONTAINER_TEST_DERIVED_FROM_MEMORY_RESOURCE_HPP
+#define BOOST_CONTAINER_TEST_DERIVED_FROM_MEMORY_RESOURCE_HPP
+
+#include <boost/container/pmr/memory_resource.hpp>
+
+class derived_from_memory_resource
+   : public boost::container::pmr::memory_resource
+{
+   public:
+   explicit derived_from_memory_resource(unsigned i = 0u)
+      : id(i)
+   {}
+
+   virtual ~derived_from_memory_resource()
+   {  destructor_called = true;  }
+
+   virtual void* do_allocate(std::size_t bytes, std::size_t alignment)
+   {
+      do_allocate_called = true;
+      do_allocate_bytes = bytes;
+      do_allocate_alignment = alignment;
+      return do_allocate_return;
+   }
+
+   virtual void do_deallocate(void* p, std::size_t bytes, std::size_t alignment)
+   {
+      do_deallocate_called = true;
+      do_deallocate_p = p;
+      do_deallocate_bytes = bytes;
+      do_deallocate_alignment = alignment;
+   }
+
+   virtual bool do_is_equal(const boost::container::pmr::memory_resource& other) const BOOST_NOEXCEPT
+   {
+      do_is_equal_called = true;
+      do_is_equal_other = &other;
+      return static_cast<const derived_from_memory_resource&>(other).id == this->id;
+   }
+
+   void reset()
+   {
+      destructor_called = false;
+
+      do_allocate_return = 0;
+      do_allocate_called = false;
+      do_allocate_bytes = 0u;
+      do_allocate_alignment = 0u;
+
+      do_deallocate_called = false;
+      do_deallocate_p = 0;
+      do_deallocate_bytes = 0u;
+      do_deallocate_alignment = 0u;
+
+      do_is_equal_called = false;
+      do_is_equal_other = 0;
+   }
+   //checkers
+   static bool destructor_called;
+
+   unsigned id;
+   void *do_allocate_return;
+   mutable bool do_allocate_called;
+   mutable std::size_t do_allocate_bytes;
+   mutable std::size_t do_allocate_alignment;
+
+   mutable bool do_deallocate_called;
+   mutable void *do_deallocate_p;
+   mutable std::size_t do_deallocate_bytes;
+   mutable std::size_t do_deallocate_alignment;
+
+   mutable bool do_is_equal_called;
+   mutable const boost::container::pmr::memory_resource *do_is_equal_other;
+};
+
+bool derived_from_memory_resource::destructor_called = false;
+
+#endif   //#ifndef BOOST_CONTAINER_TEST_DERIVED_FROM_MEMORY_RESOURCE_HPP