Static on free functions

[Dave P. via Digitalmars-d-learn]

Does `static` on a free function definition do anything?
I know the meaning of it in C, but I can’t find an equivalent 
definition  (or
any definition of it at all) when applied to free functions in 
the spec.

Are the two below any different or is it just for ease of porting 
from C?

static int foo(){
    return 3;
}

int foo(){
    return 3;
}