OK, try this - hopefully it'll make pcap headers work with DLL or non-DLL.

OK, try this - hopefully it'll make pcap headers work with DLL or non-DLL.

(This is inspired by what zlib does.  Note that WinPcap didn't decorate
anything with __declspec(dllimport) in its header files.)

There's still the issue of what we'd call a non-DLL version of libpcap
to avoid colliding with the import library we'd need to ship to support
linking with the DLL.