base release schedule

[Jeremy Huddleston Sequoia]

In https://trac.macports.org/ticket/42699, Adam pointed out to me that llvm-3.5 isn't building for him on Mavericks with released base due to the lack of -Wl,-headerpad_max_install_names.  Additionally, llvm-3.5 requires trunk base to install on Mountain Lion and earlier.

There are also a bunch of other hacks throughout dports for libc++ that will benefit from the next release of base.

According to http://trac.macports.org/roadmap, 2.3.0 is scheduled for June, but I'm wondering if we could move that up.  Specifically, what are we waiting for?

Would it be worthwhile to instead cut a 2.2.x with the configure.cxx_stdlib and -Wl,-headerpad_max_install_names changes?

--Jeremy