[athms]

No it doesn't. Only the copyright owner can re-license.

You can put modifications (that enjoy copyright protection) to BSD licensed code under the GPL or put BSD licensed code in a larger GPL code base, but you cannot re-license code covered by the BSD license.

[nmz]

I cannot tell if this is willfully pedantic or not. And well, since we are being pedantic, I guess I will allow myself to say, that you can't re-license per se, only newer versions can be re-licensed. a prior release will forever be that license.

Now, with that said, modifications made to a GPL codebase, when published must be under the GPL. This is where the virality or copyleft come in. This in turn means that a GPL codebase cannot be anything but GPL. Putting BSD licensed code inside a GPL codebase is like pouring fresh water into the ocean. And even if you did do that, it should be a separate codebase, because if its a direct modification, then that should be GPL as well.

[athms]

>...I guess I will allow myself to say, that you can't re-license per se, only newer versions can be re-licensed. a prior release will forever be that license.

Wrong. Why does the GPL crowd continue to believe they can re-license copyrighted works they don't own? Only the copyright owner has the right to re-license. The GPL does NOT give permission to re-license.

The below copyright notice is displayed in ET:Legacy source files and id Software (or a superseding entity) will hold that copyright until it expires a little over a hundred years from now.

  Wolfenstein: Enemy Territory GPL Source Code
  * Copyright (C) 1999-2010 id Software LLC, a ZeniMax Media company.

>This in turn means that a GPL codebase cannot be anything but GPL.

Wrong again. A project released under the GPL can include permissively licensed code such as BSD, MIT, or ISC. The FSF lists licenses which are compatible with the GPL. What you cannot do is change the license on that permissive code to GPL.

>because if its a direct modification, then that should be GPL as well.

It can, but nothing compels it because the original is under the another license. Also, not all modifications meet the standard to be covered by copyright; the modification must be significantly expressive.