I found out what is causing it, but I don't know how to fix it, other than turn the warning off.
This link describes the problem I am having.
Replace EXPORT in the code below with the LIBNAME_API I was talking about above and you get the idea.
#define EXPORT __declspec(dllexport)
#define IMPORT __declspec(dllimport)
#define EXPORT __attribute__((visibility("default")))
// do nothing and hope for the best?
#pragma warning Unknown dynamic link import/export semantics.
In the case of the library code, they've used the do nothing option from above, but when I replaced it with the __GNUC__ option the warning remained. Sigh...