DUB problems

[Daniel Kozak via Digitalmars-d-learn]

I try to build vibe-d Hello world app with dub, but I have many 
problems with dub, nothing works at all

Error: Output file 'client.o' for module 'vibe.http.client' 
collides with previous module 'vibe.db.mongo.client'. See the -oq 
option

and allmost nothing works as expected. How can I do one simple 
thing:

Compile vibe.d with libasync and with ldc compiler