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Fix run-tests.py -jX after 2ed667a9dfcb

Basic install:

 $ make            # see install targets
 $ make install    # do a system-wide install
 $ hg debuginstall # sanity-check setup
 $ hg              # see help

See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.