geoip.go
func SetCustomDirectory(dir string) {
	cdir := C.CString(dir)
	// GeoIP doesn't copy the string, so don't free it when we're done here.
	// defer C.free(unsafe.Pointer(cdir))
	C.GeoIP_setup_custom_directory(cdir)
}
func SetCustomDirectory(dir string) {
	cdir := C.CString(dir)
	// GeoIP doesn't copy the string, so don't free it when we're done here.
	// defer C.free(unsafe.Pointer(cdir))
	C.GeoIP_setup_custom_directory(cdir)
}
// SetCustomDirectory sets the default location for the GeoIP .dat files used when
// calling OpenType()