OpenBSD libobjc2 now linking against libdispatch

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