Sqlite has a really nice solution for this, by the way. Their code is public domain. If you happen to live in a place that doesn't have a well formed notion of public domain and that's going to cause you a problem (SQLite's never gonna come after you, but maybe your own government will?), for 6 grand the sqlite guys will sell you an sqlite licence that is basically just a well formed concept of public domain, and then use the money to fund more sqlite development.

https://www.sqlite.org/copyright.html