I don't think Apple is aiming for "a compiler which prioritizes stability and correctness over new functionality and optimizations". I haven't checked, but I would not be surprised if they have cases where the compiler shipping with Mac OS X 10.q is obsoleted before they ship Mac OS X 10.q+1 a year later. Also, I think clang was the first compiler to claim to fully support C++ 11,
As to the subject at hand: OpenBSD aims for an OS "which prioritizes stability and correctness over new functionality and optimizations". Such an OS will want to use a similar compiler. And yes, I think one can draw an analogy between gcc/egcs and BSD/Linux here.
Didn't Clang/compiler-rt have full support before GCC/libcxx (or whatever it's called) did? In my mind, and the minds of most others, this means actual full C++1 support. GCC claimed it early, but only because the compiler supported it fully, though afaict there were features which weren't supported in the runtime. Clang/compiler/rt fully support the language, and I believe they were the first to do so.
Does that mean that clang passed the finish line earlier? Maybe, but it could just be that the gcc project looks harder for bugs in their own project, thus placing their finish line farther out.
Frankly, it doesn't really matter who was first. It's way more important to know whether the compilers generate correct code and if they do, that it is efficient.
As to the subject at hand: OpenBSD aims for an OS "which prioritizes stability and correctness over new functionality and optimizations". Such an OS will want to use a similar compiler. And yes, I think one can draw an analogy between gcc/egcs and BSD/Linux here.