hashdist/hashdist — pull request #195 by ahmadia (2014-02-21 22:32:21+00:00)
Title: Silently pass {{undefined}} as empty strings

This corrects to the intended behavior of an earlier patch which
intended to create this functionality.

Undefined flags such as {{build_with}} no longer need to be specified in
profiles. It is my intention that we will eventually add package-level
defaults, since implicit behavior can be dangerous to users.