clone: save hardlink state of util.copyfiles() When trying to do hardlink-cloning, the os_link() call of the first file tried already fails on Windows, if the source is on a UNC path. This change avoids calling os_link() for the rest of files, leaving us with a *single* failed os_link() call per clone operation, if the source can't do hardlinks.

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

Merge with stable

status: avoid performance regression when no .hgsub is present (introduced by 24ce8f0c0a39)

doc: document expansion of %include and ui.username

ui.username(): expand environment variables in username configuration value. note: expansion of config variables must be handled on a case-by-case basis because they can contain arbitrary data that may not be desirable to expand.

config: expand hgrc %include paths