Future version of libgc may allow us to implement ephemerons (and SRFI 124)

[jpellegrini]

In the changelog for the development version (8.3.0) of libgc, https://github.com/ivmai/bdwgc/blob/master/ChangeLog there is this:

• Add callback API to support ephemeron marking

It seems that this could, perhaps, be used to implement SRFI 124. :eyes:

I thought I'd file an issue as a reminder.

[jpellegrini]

Or maybe it's an internal thing. I'll keep reading (it it's there, it's undocumented)