Checks for missing shared library dependencies in the IOU image.

def _library_check(self):
        """
        Checks for missing shared library dependencies in the IOU image.
        """

        try:
            output = yield from gns3server.utils.asyncio.subprocess_check_output("ldd", self._path)
        except (FileNotFoundError, subprocess.SubprocessError) as e:
            log.warn("Could not determine the shared library dependencies for {}: {}".format(self._path, e))
            return

        p = re.compile("([\.\w]+)\s=>\s+not found")
        missing_libs = p.findall(output)
        if missing_libs:
            raise IOUError("The following shared library dependencies cannot be found for IOU image {}: {}".format(self._path,
                                                                                                                   ", ".join(missing_libs)))