This doesn't work on Linux, sadly.

Maybe change this to:

```
ifeq ($(UNAME),Darwin)
  TARGET_LIB=_cudaconv2.dylib
  LINK_FLAGS="-lpython -shared"
else
  TARGET_LIB=_cudaconv2.so
  LINK_FLAGS="-shared"
endif
...

${TARGET_LIB} : ${OBJ}
 nvcc ${LINK_FLAGS} -o $@ $^

```