msys, swig, cmake, and undefined octave dll routines

[Brad Bell]

I am not sure if this is the right list for the question below ?

I am working on a swig prototype that interfaces CppAD Algorithmic 
Differentiation to octave, python, and perl. That should be enough to 
know it would work in general; see
    https://github.com/bradbell/cppad_swig

The python version works under mingw-msys, but I am having some trouble 
linking the octave version. For example, I get the message
    swig_exampleOCTAVE_wrap.cxx:912: undefined reference to `
    octave_value::octave_value(std::__cxx11::basic_string<char, 
std::char_traits<char>, std::allocator<char> > const&, char)'

my CMakeLists.txt code is locating the octave libraries that have a 
dll.a extension, to be specific
    -- octave_liboctinterp = 
C:/Octave/Octave-4.0.0/lib/octave/4.0.0/liboctinterp.dll.a
    -- octave_liboctave = 
C:/Octave/Octave-4.0.0/lib/octave/4.0.0/liboctave.dll.a

It seems to me that these are import libraries because the have the 
'.dll.a' extension; see Answer 1 on
http://stackoverflow.com/questions/6422478/linking-a-lib-and-def-files
I cannot find the corresponding liboctinterp.dll and liboctave.dll to 
make sure they are in my windows path (so that the system can find them 
for dynamic linking). Is there some other dll that I am missing or do 
the '*dll.a' files contain the required routines and I just have the 
wrong linking conventions ?