I think I remember that they were even trying to move away from gcc to something home-grown and simpler, since gcc is such a huge dependency and even uses c++ now.
You remember pcc, "Portable C Compiler", which, though currently actively developed [0], has a not-so-dependable history. 1.0 released in 2011, 1.1 in 2014, and no releases since.
pcc was merged in, but with the spotty history, taken out of base again.
> Weren't the OpenBSD pretty clang-hostile a few years back?
Not quite. LLVM was evaluated for the main compiler back in 2013 [1], but the main drawbacks was LLVM can't be used for every platform that OpenBSD supports. They also go on to talk about how every open compiler is painful, because there are no LTS releases. Compiler bugs were a major problem for OpenBSD, and I doubt its changed enough for that to not be the case.
[0] Mailing list is still going strong, and patches are still coming in and merging. (http://marc.info/?l=pcc-list)
[1] Long read, but in-depth: http://marc.info/?l=openbsd-misc&m=137530560232232