Misleading "must be able to find libstdc++4.7 or newer" message

Hi all,

When I do a vanilla CMake build of clang svn trunk on OS X 10.7, I get this:

CMake Error at cmake/modules/HandleLLVMOptions.cmake:37 (message):
   Host Clang must be able to find libstdc++4.7 or newer!
Call Stack (most recent call first):
   CMakeLists.txt:301 (include)

I realize I just need to turn LLVM_ENABLE_LIBCXX on, but that error message seems pretty misleading to me. Seems like it should say "libstdc++4.7 or newer **or libc++ x.y or newer**". Some people may go looking to install libstdc++4.7 on their Mac when the OS-provided libc++ will do. Better yet, why can't it just find libc++? Or am I missing something?


On OS X, we should just default to enabling LLVM_ENABLE_LIBCXX. That seems fair.