You can write an MC++ module, which does a LoadLibrary and GetProcAddress
then function call.

Example:
You need to use API MyApi in unknown dll. Say MyApi is defined as

int MyApi(int input).

You will define an API called
int MyApiShim(LPWSTR dllname, int input).

It does a LoadLibrary(dllname), GetProcAddress(handle, MyApi), then call
MyApi.

In your main app, you define a DllImport of MyApiShim on your MC++ module.