Compile-Time Only Function

[Moinak Bhattacharyya via Digitalmars-d]

Is there an annotation that declares a function compile-time 
only? I'm attempting to use a mixin string generating function 
that uses standard druntime imports, but I'm working in a 
no-stdlib environment. I never need to use this function at 
runtime (as is the case, I imagine, with a great many of mixin 
string generating functions) so is there a way I can omit it?