The unpacked and unmodified WCSLIB distribution is placed in this directory.
The Kapteyn Package's setup.py script uses its sources when building the
kapteyn.wcs module. When a new version of WCSLIB is released, the old one
can be removed and replaced by the new one. The WCSLIB distribution's
directory name must start with "wcslib". Until now this has always
been the case.
