Research, so far, has determined there are two available C/C++ Glulx interpreter engines for Interactive Fiction:
Glulxe at https://github.com/erkyrath/glulxe
Git at https://github.com/DavidKinder/Git
So far, my experience has found both to be interchangeable in most cases. However, Glulxe has compiler conditions to support Superglús superglus.com stories. It's great to have choices that are being maintained by the community.