Saw this on the Tcler's Wiki. I don't know who the poster is, but most likely this is Linux, which often has gcc installed:

Wow. I've never ever used critcl before. Now I'm convinced. I didn't even know I had critcl on my system, but the above cut'n'pasted and Just Worked. Nifty.

Scripting with a C compiler built-in. A few years from now, most people will get their first exposure to C this way. Quite a difference from how old-timers like me had to make things work!