util.copyfiles: don't try os_link() again if it failed before If the os_link() call on the first file in the directory fails [1], we switch mode to using shutil.copy() for all remaining files. [1] happens for example on Windows for every file when cloning from a UNC path without specifying --pull.

cmdutil: cleanup imports

make transactions work on non-refcounted python implementations

mq: support multiple patch queues using qqueue