PR 28819/28834 review

[Gagan Sidhu]

https://github.com/macports/macports-ports/pull/28834
https://github.com/macports/macports-ports/pull/28819

need someone to review these PRs.

clang doesn't finish within the 6 hour timer, but will build and work properly on 10.6+ for intel macs if someone decides to evaluate it.
	-it takes about 2 hours in a 10.6 VM with 16 cores and 16GB of ram. 

would appreciate pushing these, though i'm not sure how buildbot will distill the PRs to ready-made libraries for macports-libcxx, which will spare the leechers from having to endure what i have in testing and building the compiler (probably) 30+ times.