Symbol not found error

[DRoscoe]

I am building an iOS app using QtQuick (5.4.1). I can build and run in the simulator, but when I try to install a release build, the final link step fails with the following error:

Undefined symbols for architecture arm64:
  "std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::operator<<<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
      operator<<(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, aop_xml::DOMString const&) in libaop_xml.a(DOMString.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

This looks like a c++ library problem, but I don't know how to resolve it. The xCode project file is being generated using qmake with the following command line:

/Users/droscoe/Qt/5.4/ios/bin/qmake -spec macx-xcode -recursive

I would appreciate any help