bug#40842: uwsgi python plugin not found

[John D. Boy]

Here's what happens when I try to run an uwsgi process with the Python plugin.

$ guix environment --pure --ad-hoc python uwsgi uwsgi:python
$ uwsgi --ini uwsgi.ini 
[uWSGI] getting INI configuration from uwsgi.ini
open("/gnu/store/xmc67azy4vk3mcpyg3qy6vc2wq3v127w-uwsgi-2.0.18/lib/uwsgi/python_plugin.so"):
 No such file or directory [core/utils.c line 3724]
!!! UNABLE to load uWSGI plugin: 
/gnu/store/xmc67azy4vk3mcpyg3qy6vc2wq3v127w-uwsgi-2.0.18/lib/uwsgi/python_plugin.so:
 cannot open shared object file: No such file or directory !!!

The problem is that uwsgi looks for the plugin in the wrong place. The uwsgi 
package has two outputs ("out" and "python"), and the Pyton plugin goes into 
the latter (/gnu/store/...-uwsgi-2.0.18-python/lib/uwsgi). 

Unfortunately my packaging skills aren't (yet) good enough to figure out how to 
make the package aware of the proper plugin path. 

John