Not exactly, but under US copyright law there is a limitation of exclusive rights that grants the owner of a copy the right to make an adaptation provided "that such a new copy or adaptation is created as an essential step in the utilization of the computer program in conjunction with a machine and that it is used in no other manner". Unfortunately, the law doesn't specify what "adaptation" means, and I'm not sure the concept of an "essential step" stretches to cover modifying your program to run on a new OS decades after its original host platform has gone extinct.

Regardless, making such a modification for personal use only would be hard for a copyright owner to win a lawsuit over even if they could find out about it. But publicly distributing your derivative work like this is definitely violating the original's copyrights.