Clang uses wrong include headers when compiling 32 bit on 64 bit ubuntu

64-bit clang uses 64-bit headers when compiling 32-bit code. GCC works correctly.

This example program reproduces the problem:

#include <fstream>

int main(void)
{
  std::ifstream in( "test.dat" );
  in.rdbuf()->pubseekoff( 0, std::ios::beg, std::ios_base::in );
}

This can then be built with:

#!/bin/bash
BUILD=clang++
#BUILD=g++
$BUILD -m32 -c test.cpp
$BUILD -m32 -v test.o

Which produces a link error with clang but not with gcc:
test.cpp:(.text+0x76): undefined reference to `std::basic_streambuf<char, std::char_traits<char> >::pubseekoff(long, std::_Ios_Seekdir, std::_Ios_Openmode)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

All the above was done on Ubuntu 12.04 64 bit with clang 3.0-6ubuntu3