Issue with Rcpp -- gcc vs clang++

doit.R

library(Rcpp)
Sys.setenv("PKG_CXXFLAGS" = "-std=c++11")
sourceCpp("tuple.cc",verbose=TRUE)

doit2.R

library(Rcpp)
Sys.setenv("PKG_CXXFLAGS" = "-std=c++11 -DUSE_DELETER")
sourceCpp("tuple.cc",verbose=TRUE)

tuple.cc

#include <Rcpp.h>
#include <tuple>


/*
  Linking fails on GCC unless I use the block below that puts an overload of standard_delete_finalizer in ns Rcpp.

  (I can also provide my own custom deleter, a la std::unique_ptr, which works fine.)

  All is good with clang++ however

  The type of error message I get with g++ 4.92 is:
  Error in dyn.load("/tmp/RtmpmRO8Pk/sourcecpp_43e839c52664/sourceCpp_49632.so") : 
  unable to load shared object '/tmp/RtmpmRO8Pk/sourcecpp_43e839c52664/sourceCpp_49632.so':
  /tmp/RtmpmRO8Pk/sourcecpp_43e839c52664/sourceCpp_49632.so: undefined symbol: _ZN4Rcpp25standard_delete_finalizerISt5tupleIIiiEEEEvPT_
*/

#ifdef USE_DELETER
namespace Rcpp {
  template<>
  inline void standard_delete_finalizer<std::tuple<int,int> >( std::tuple<int,int> * t ) { delete t; }
}
#endif

//Pretend that this is a namespace in another header-only Rcpp-based library
namespace foo {
  /*
    This appears to be the culprit.

    If I do not use this typedef, all is good with GCC.

    However, I want this type so that I can:
    1. refer to it when SEXPs are passed to other functions.
    2. Change what the type is and not have to find all the places
    where it is referred to and change them, too.
  */
  using tuple_t = std::tuple<int,int>;

  /*
    Note: if foofunc is NOT a template,
    everything "just works" as expected,
    but we're trying to get a set of templates
    gluing an existing header-only C++11 library
    and Rcpp, in order to provide access to the former
    in R.
   */
  template<typename T>
  SEXP foofunc()
  {
    return Rcpp::XPtr<tuple_t>(new tuple_t(T(),T()));
  }
}

//' Pretend that this is some function using our new "glue" library with a concrete type
// [[Rcpp::export()]]
SEXP foofunc_caller() { return foo::foofunc<int>(); }