With Clojure being available for the jvm, the clr through ClojureCLR and javascript through ClojureScript I don't believe that this will be much of an issue.
Except that ClojureScript is dependent on JVM Clojure, and if ClojureCLR were to take advantage of the CLR's capabilities (TCO and stack allocation, for example) it also wouldn't be Clojure.
So we're really talking about dialects of Clojure (and perhaps might as well be talking about dialects of Lisp in general).
We're not that far from officially having a boostrappable ClojureScript compiler. And some people have already done it - http://github.com/kanaka/clojurescript