Hi, FYI: I finally updated libobjc2 to 2.3 on OpenBSD [1], and since this version allows to make use of the Blocks runtime from libdispatch, this finally allows linking against libdispatch and makes GCD available. This was quite a bit of an adventure ;) With that, all modern objc features should be available on OpenBSD when you install packages. Snapshot packages should hit the distribution servers soonish, and it will be in the next release.
cheers, Sebastian [1] https://marc.info/?l=openbsd-ports-cvs&m=176997534423417&w=2
