dick1982: I'm guessing they're not using SCUMMVM because of possible copyright issues in the future? the original SCUMM should still own by lucasfilm games. but SCUMMVM is under GPL and that might have other issues like this.
http://sev-notes.blogspot.sg/2009/06/gpl-scummvm-and-violations.html then again, same thing can be said for dosbox. so i guess gog's tech staff just prefer working with Dosbox/SDL ?
Complying with the GPL is pretty easy. You just have to do it.
Compared with other licensing or contractual negotiations, the requirement are trivial. You provide the source in the download, or you provide a .tar of it on your website and include a url in the download.
The situation that happened with Atari is pretty similar to one where when making a game they just illegally used some code from another company they found and did not license it or work out a contract for the use of it. The difference is that it's quite easy to correct by providing information to your users of "hey, the gpl software in this product is availble at this url", where with misappropriation of typical code, the correction is being sued for millions of dollars. The only reason this was difficult to do for Atari is that:
* They were doing boxed software, where changing it later is difficult
* They were linking the code fairly directly with other code they don't want to share
GOG.com is in an easy position to satisfy the GPL, doing the ScummVM packaging themselves, so they can just provide the information and URL in the installer and/or an accompanying textfile. Problem solved.
In the worst case, if an error is made, they can update the packages to come into compliance by providing a url in the package and providing the scummvm source on their domain / CDN.