title: boost::date_time, g++-4.7.0, compile error
body: <p>The following code gives compile error with g++-4.7.0 but compiles fine with g++-4.6.</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;boost/date_time/local_time/local_time.hpp&gt;
  using namespace std;
  int main(){
      boost::posix_time::ptime time_t_epoch(boost::gregorian::date(1970,1,1));
      cout &lt;&lt; time_t_epoch &lt;&lt; endl;
      return 0;
  }
  </code></pre>
  
  <p>The following is the error message that is repeatedly seen (compiler outputs a lot of messages) </p>
  
  <pre><code>/usr/include/boost/date_time/local_time/local_date_time.hpp:433:84: error: use of deleted function boost::shared_ptr&lt;boost::date_time::time_zone_base&lt;boost::posix_time::ptime, char&gt; &gt;::shared_ptr(const boost::shared_ptr&lt;boost::date_time::time_zone_base&lt;boost::posix_time::ptime, char&gt; &gt;&amp;)
  </code></pre>
  
  <p>I am using Ubuntu 12.04 and libboost-date-time1.46.1.</p>
  
  <p>Any suggestions?</p>