"Non-commercial" is apparently a huge can of worms. You could try something along the lines of "if you distribute binaries, you must do so under an OSI-approved

"Non-commercial" is apparently a huge can of worms. You could try something along the lines of "if you distribute binaries, you must do so under an OSI-approved license" (or pay for a "commercial" license, obviously). This isn't perfect (people could use your compiler to compile serverside software "for free"), but at least it's unambiguous.