I knew someone was gonna call me on that one. :) What I mean is desktop machines (as opposed to servers) running one of the free OSes are very nearly always equipped with a gcc. It's certainly not an absolute truth, but one can presume the availability of a compiler in reasonably large percentile of their target market. Certainly, it's much more valid to do so than when targetting Windows or Mac (though OS X is a slight change of course, in that even though AFAIK it does not ship with a compiler, a free one is available).

Makeshifts last the longest.