Excluding symbols

[Etienne via Digitalmars-d]

I've been using a lot of CTFE in my libraries and this has had the side 
effect of increasing my link time beyond 13 seconds. There's a pretty 
big chunk of those symbols being exported that are used only for 
evaluating mixins.

Would there be a way to specify something in the lines of `extern 
(none):` or `intern:`?