Hide some internal symbols for memory resource.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@275089 91177308-0d34-0410-b5e6-96231b3b80d8

src/experimental/memory_resource.cpp

@@ -61,6 +61,8 @@ protected:
     { return &__other == this; }
 };
 
+namespace {
+
 union ResourceInitHelper {
   struct {
     __new_delete_memory_resource_imp new_delete_res;
@@ -74,6 +76,9 @@ union ResourceInitHelper {
 // Only in C++11 is "init_priority" needed to ensure initialization order.
 ResourceInitHelper res_init __attribute__((init_priority (101)));
 
+} // end namespace
+
+
 memory_resource * new_delete_resource() _NOEXCEPT {
     return &res_init.resources.new_delete_res;
 }