Like C extern pragma?

[Lachu]

I found information about extern pragma, but It don't describe what it does. I 
need C-like extern pragma or way to use only function prototype (and include 
file with these prototypes). That's because I have problem with circual import 
of modules. Nim compiler complain about missing function implementation, when I 
tries to do that (only declaration of function in file, implementation in 
another).