Override -shared option in g++ - c++

Question

I was building some Cython extensions, and have to link it against a static library (it has CUDA code in them, so have to be static):
running build_ext
building 'k3lib' extension
gcc -pthread -B /home/kelvin/anaconda3/envs/torch/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/kelvin/repos/tools/include -I/home/kelvin/anaconda3/envs/torch/include/python3.8 -c main.cpp -o build/temp.linux-x86_64-3.8/main.o -O3 -march=native
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
g++ -pthread -shared -B /home/kelvin/anaconda3/envs/torch/compiler_compat -L/home/kelvin/anaconda3/envs/torch/lib -Wl,-rpath=/home/kelvin/anaconda3/envs/torch/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.8/main.o /home/kelvin/repos/tools/include/libk2.a -L/home/kelvin/repos/tools/include -lk2 -o build/lib.linux-x86_64-3.8/k3lib.cpython-38-x86_64-linux-gnu.so -static -Wl,-Bstatic -flinker-output=exec
However, Cython's g++ compile command includes the options -shared -fPIC by default. I tried a number of options at the end of the command via this setup file (the static library is at $(LOCAL_INCLUDE)/libk2.a):
includes = [os.getenv("LOCAL_INCLUDE")]
ext_modules = [
Extension("k3lib", sources=["main.pyx"],
libraries=["k2"], include_dirs=includes, library_dirs=includes, language="c++",
extra_compile_args=["-O3", "-march=native"], extra_objects=[f"{includes[0]}/libk2.a"],
extra_link_args=['-static', '-Wl,-Bstatic', '-flinker-output=exec'])
]
#extra_objects=[f"{includes[0]}/libk2.a"]
#extra_link_args=['-static']
setup(name="k3lib", ext_modules=cythonize(ext_modules, language_level="3"))
Still, g++ thinks that I want to build a shared library, and thus the error message. Is there a way to override the -shared option? I'm planning to go into Cython's files and edit them myself, but was wondering is there a simpler way?
Context: I was following this question on SO but can't replicate their success.