title: IOS7 (only) stdlibc++ linking issue
body: <p>I need help.
  I had a framwork which was using stdc++ like std:string.
  Now when i have created new app for IOS7 only there is problem with linking this framework because of problems with stdc++ lib:</p>
  
  <p>Undefined symbols for architecture armv7
  "std::basic_string, std::allocator >::_Rep::_S_empty_rep_storage", referenced from ...</p>
  
  <p>I have find out something strange that when i change the Deplyment target to ios6 in this app all is working fine.
  With ios7 i see errors.</p>
  
  <p>I already have flag set in other linker flags: -lstdc++ </p>
  
  <p>Any idea what ami doing wrong?</p>