为什么Cython编译器使用后缀“cpython-35m-x86_64-linux-gnu.so

#setup.py    
from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(
    cmdclass = {'build_ext': build_ext},ext_modules = [Extension("module_name",["xxxx.pyx",'./yyyyy.c'],language='c',extra_compile_args = ['-std=gnu11'],extra_link_args=['-std=gnu11']                 
                    )]
)


$python --version
Python 3.5.1
$python -c "import cython; print(cython.__version__);"
0.25.2
$python setup.py build_ext -i

问题>为什么Cython将模块名称生成为module_name.cpython-35m-x86_64-linux-gnu.so而不是module_name.so？

谢谢