What kind of patents do they have on the compiler tech, and is there any guarantee they won't go after you for using it? edit: Ah nice, Apache 2 license explic

What kind of patents do they have on the compiler tech, and is there any guarantee they won't go after you for using it? edit: Ah nice, Apache 2 license explicitly calls out a patent license is granted for use. I wonder how much cajoling it took to get the lawyers to agree to that!