[Bro-Dev] #388: Fix more compiler warnings

[Jonathan Siwek]

> One question would be whether it's acceptable to add a configure option 
> that compiles with -Werror and then do the NMI builds with that….

I think what we want is for the build to complete even if there's warnings so that the tests can still run.  i.e. A given NMI job submission should tell us the most information as we can get from it.

- Jon