Need reviewer - jdk7u-osx Mac sanity check fixes

[Henri Gomez]

> The JDK should be buildable under both llvm-gcc (which it currently uses) and clang, which is the future, since llvm-gcc is now in maintenance mode.
>
> If you are restricting your builders to Mac OS X 10.7 now, you can actually cut over to using clang soon, since it has no known bugs compiling the JDK (right Alex? I'm not completely hallucinating this right?)

Why OpenJDK 7 should be restricted to 10.7 ?