Host Clang must be able to find libstdc++4.7 or newer!

I'm suffering through a Cmake build of Clang 3.6. I'm experiencing an
error "Host Clang must be able to find libstdc++4.7 or newer!".
(Suffering because I know this process does not work with
Autotools/Makefiles; so I'm trying Cmake but I know nothing about
Cmake).

I'm using a recipe that can be found at "Clang 3.6 Recipe with libc++
and libc++abi", Clang 3.6 Recipe with libc++ and libc++abi - Pastebin.com. It simply fetches
components with wget, unpacks them in-tree, configures and then kicks
off a build. The components that have been downloaded and placed
in-tree are:

  * LLVM
  * Clang Front End
  * Compiler-RT
  * Tools Extra
  * libcxx
  * libcxxabi

From the build/ directory (and on OS X 10.8.5) I issue the following:

    cmake V=1 --enable-optimized --enable-cxx11 --enable-libcpp
--prefix=/usr/local ../llvm

It results in the the error below. Adding `--with-libcxx
--with-libcxxabi` results in the same error.

Line 38 of HandleLLVMOptions is shown after the error. I think its due
to the LLVM_NO_OLD_LIBSTDCXX.

There's a thread with a similar error at
'Re: [cfe-dev] Using Xcode to compile clang, still possible ?' - MARC. But as a completely
inexperienced Cmake user, I really can't follow what's being said or
what I should do to resolve the issue.

I thought placing things in-tree was the magic to make
auto-configuration work. I'm not sure if I was mistaken or if I'm
seeing a small issue in configuration.

Does anyone have any ideas how to I can tell the build system I am
trying to build libc++ and libc++abi, and it should not look for it?

Thanks in advance.