Re:Building and Running .NET’s CoreCLR on OS X
by praeclarum on Tuesday February 10, 2015 @01:14PM
(#9028810)
Mono has a lot of GPL code. Xamarin has a license to impart commercial licenses to their customers. So Xamarin customers are fine. Mono users will have to abide by the GPL'd bits.
Microsoft's CoreCLR is MIT licensed. Nice. :-)