man.output.base.dir — Specifies separate output directory
The man.output.base.dir parameter
specifies the base directory into which man-page files are output. The
man.output.subdirs.enabled parameter controls
whether the files are output in subdirectories within the base
directory.
The values of the man.output.base.dir
  and man.output.subdirs.enabled parameters are
  used only if the value of
  man.output.in.separate.dir parameter is
  non-zero. If the value of the
  man.output.in.separate.dir is zero, man-page
  files are not output in a separate directory.