How to prevent use of clang && llvm?

[Chris H]

Greetings,
 I'm in the process of performing an upgrade, and ran a preliminary check
to see what would be performed. During the process I encountered a
dialog(1) for both clang, and llvm3. It was for textproc/clucene. Which
wants devel/boost-libs, which depends on devel/boost-jam. I didn't require
clang, or llvm3 with the initial install of textproc/clucene (that I can see/recall).
But am presented with the dialog this time. I have WITHOUT_CLANG=true
in /etc/src.conf. Do I need to also add it to /etc/make.conf? Anything else?

Thank you for all your time, and consideration.

--Chris