extern boost::filesystem::path mo_path ();
#endif
extern std::string tidy_for_filename (std::string);
-boost::shared_ptr<const libdcp::Signer> make_signer ();
+extern boost::shared_ptr<const libdcp::Signer> make_signer ();
+extern libdcp::Size fit_ratio_within (float ratio, libdcp::Size);
struct FrameRateConversion
{