Using MPolynomial_libsingular in Cython code

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I wrote some Sage code to deal with multivariate polynomials (over QQ say). In order to increase performances, I tried to cythonize the file, and in particular to add static types. I was able to add types for basic types (such as int or list¹) but I am not able to use the type MPolynomial_libsingular. I tried to import Mpolynomial_libsingular with either import or cimport. A minimal example (file named essai.spyx):

from sage.rings.polynomial.multi_polynomial_libsingular import MPolynomial_libsingular # or cimport
cpdef MPolynomial_libsingular dummy(MPolynomial_libsingular p):
    return p

I give below the result I get when I call sage essai.spyx, first with import and then with cimport:

1. With import:

   Compiling essai.spyx...
   Traceback (most recent call last):
     File "/home/bruno/Software/sage/src/bin/sage-run-cython", line 8, in <module>
       s = load_cython(sys.argv.pop(1))
     File "/home/bruno/Software/sage/local/lib/python2.7/site-packages/sage/repl/load.py", line 65, in load_cython
       mod, dir = cython(name, compile_message=True, use_cache=True)
     File "/home/bruno/Software/sage/local/lib/python2.7/site-packages/sage/misc/cython.py", line 469, in cython
       raise RuntimeError("Error converting {} to C:\n{}\n{}".format(filename, log, err))
   RuntimeError: Error converting essai.spyx to C:
   
   
   Error compiling Cython file:
   ------------------------------------------------------------
   ...
   include "cysignals/signals.pxi"  # ctrl-c interrupt block support
   include "stdsage.pxi"
   
   include "cdefs.pxi"
   from sage.rings.polynomial.multi_polynomial_libsingular import MPolynomial_libsingular
   cpdef MPolynomial_libsingular dummy(MPolynomial_libsingular p):
        ^
   ------------------------------------------------------------
   
   _home_bruno_Recherche_Sage_LinearFactors_essai_spyx_0.pyx:7:6: 'MPolynomial_libsingular' is not a type identifier
   
   
   Error compiling Cython file:
   ------------------------------------------------------------
   ...
   include "cysignals/signals.pxi"  # ctrl-c interrupt block support
   include "stdsage.pxi"
   
   include "cdefs.pxi"
   from sage.rings.polynomial.multi_polynomial_libsingular import MPolynomial_libsingular
   cpdef MPolynomial_libsingular dummy(MPolynomial_libsingular p):
                                      ^
   ------------------------------------------------------------
   
   _home_bruno_Recherche_Sage_LinearFactors_essai_spyx_0.pyx:7:36: 'MPolynomial_libsingular' is not a type identifier
   

2. With cimport, I get also a RuntimeError, but with many more errors. You can read the complete log file. Here is an excerpt:

   In file included from /home/bruno/Software/sage/local/include/factory/factory.h:45:0,
                    from /home/bruno/Software/sage/local/include/factor.h:8,
                    from _home_bruno_Recherche_Sage_LinearFactors_essai_spyx_0.c:249:
   /home/bruno/Software/sage/local/include/factory/templates/ftmpl_array.h:19:10: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
    template <class T>
             ^
   

Question: What am I doing wrong, and what is the correct way of cythonizing such a file?

¹ An aside question: Is there a way to specify the type of elements in a list? Something like list<int> (this does not work)?