local Code completion database?

[kitts]

I recently, have compiled 3.4beta2 and have noticed a few things with the 
code completion on which i would like a better understanding.

When i have an automake based project, code completion generally works 
better. It is able to pick functions from other files in the project and 
offer them for completion. And in the times that it fails to offer to 
complete the function name, it still manages to offer parameter listing.

When have a custom makefile based project, code completion does not seem to 
work. It has always worked with respect to local variables in context but 
not otherwise even if the function is in the same file.

Now, what i would like to know is how does it build its code completion 
database? In a custom makefile project, would it manage to parse the 
makefile and be capable of identifying files involved in the project? Or do 
have to explicitly ask it to include certain files?
-- 
Cheers!
kitts