Bug#803564: python-mapnik uses wrong lib-directory

[Tobias Wendorff]

Package: python-mapnik
Version: 1:0.0~20151022-ab8b1f6-1 and others

I've just backported mapnik 3.0.8 from Debian Sid to Debian Jessie. Quiet
easy, but after installing python-mapnik, Mapnik complained about the
datasource plugin directories not being registered.

After doing some tests with mapnik-config, ldd and ctypes, I've found the
problem in paths.py in dist-/site-packages. The setup sets mapniklibpath
to lib_path + "/mapnik". On Debian, Mapnik3 gets installed to
''/usr/lib/mapnik/3.0"; the missing plugins are in its subdirectory input.
The installer sets the path to /usr/lib/mapnik[/input] instead of
/usr/lib/mapnik/3.0[/input], which leads to the problem reported.

Since mapnik-config finds the correct path, please use this output instead
of a hardcoded string in
https://github.com/mapnik/python-mapnik/blob/master/setup.py

Read more about it here:
https://github.com/mapnik/python-mapnik/issues/62