Strange problem when using Futhark

[PMunch]

That is because Futhark only imports the symbols found directly within the 
specified files. I plan to add a feature where it will import all symbols from 
files in a folder but until that lands you need to import the files manually. 
This means you need to figure out which header file actually defines that and 
import it as well. Note that Futhark also has pretty rudimentary macro support, 
so if it is a macro it might not work and you'll have to define it yourself.