...and it only took 26 years! Ludovic Courtès has just applied my thread cancellation patch -- my first patch accepted, ever -- to the HEAD of GNU Guile. It took me forever to get working, and then another week or two of hand-wringing over copyright assignment and the disclaimer from my employer, but it's in! Thanks are due to Ludovic, whose patience was... epic.
This paves the way for the implementation of SRFI-18 that I'm working on, which I think will be pretty useful in terms of making Guile more competitive with other Scheme platforms.