the build directory; with this option you can select a different cache
directory (the doctrees can be shared between all builders).
+ Distribute the build over *N* processes in parallel, to make building on
+ multiprocessor machines more effective. Note that not all parts and not all
+ builders of Sphinx can be parallelized.
+ This option should be considered *experimental*.
Don't look for the :file:`conf.py` in the source directory, but use the given