"fd must be non-negative: -1" when specifying several identical sockets in gevent mode

[soon]

Running the following app:

def application(e, sr):
    sr('200 OK', [('Content-Type', 'text/html')])
    return [b"Hello World"]

With these parameters:

uwsgi --socket ./gevent.socket --socket ./gevent.socket --module gevent_example --gevent 100

Results in

Traceback (most recent call last):
  File "src/gevent/libev/corecext.pyx", line 674, in gevent.libev.corecext.loop.io
  File "src/gevent/libev/corecext.pyx", line 1052, in gevent.libev.corecext.io.__cinit__
ValueError: fd must be non-negative: -1

This does not happen if we omit --gevent 100