One of the early limitations to the ever-popular Xbox One feature, Backward Compatibility, was the limitation in exactly which titles can be supported. The ability to install and run multi-disc Xbox 360 games on the Xbox One was one such limitation, and according to a post on reddit (via Windows Central), that's made a change for the better.
None other than Xbox Live's own Major Nelson (Larry Hryb), mulit-disc titles are now supported in Backward Compatibility:
I can confirm that the BC team has done work to support multi disc scenarios. Be sure to thank the BC engineers.
As Windows Central pointed out, the capability has already been proven with the inclusion of Deus Ex: Human Revolution Director's Cut to the Backward Compatibility list. And so if you have any multi-disc Xbox 360 titles hanging around your collection, take heart--it's entirely possible that you'll soon be able to run them on your Xbox One in spite of their multi-disciness.