Radu-Adrian Popescu <radu(dot)popescu(at)aldratech(dot)com> writes:
> Doug Quale wrote:
>
> | The Postgres license is a free software license that is GPL
> | compatible.
>
> Where GPL compatible means (possibly among other things) that I can get
> a BSD-licensed Postgresql and turn it into a GPL-licensed MyPostgresql ?
Absolutely. This has been done. For example, GNU bison was derived
many years ago from Berkeley yacc.
You can go further and make a non-free MyPostgresql. Use Postgres
code in a completely proprietary project if you like. The X11 license
places far fewer restrictions on code than does the GPL. Works
derived from X11-licensed code do not have to be free.