I'd like to focus this issue a bit. Antoine originally proposed that non-Python code might want to access libmpdec. However, given that this is now a separate project (as it seems), I don't think it's Python's task to make the API available. If it is a separate library really, you shouldn't need to link to Python in order to use it. IOW, the solution should be to use the system libmpdec.

So the focus should be on other Python C modules that want to access decimal objects. Are there precedents of such modules? What API features do they actually need?