I download libcxx code from
http://llvm.org/svn/llvm-project/libcxx/tags/RELAESE_30/final, then goto
${libcxx-path}/lib directory and executed ./buildit.
It default used clang++ to compile, but there were some errors:
I recommend just getting tip-of-trunk:
http://llvm.org/svn/llvm-project/libcxx/trunk
It is in good shape and has lots of bug fixes since that tag was made (last November). That being said, I don't recognize the error you're seeing.
If the errors continue, let us know what platform you're compiling on.
Howard
I compiled libcxx on Linux( RHEL6, X86_64).
And another question:
Under the libcxx/tags directory, which is the newest release version of
libcxx, libcpp-31 or RELEASE_30/final?
Thanks Howard !
libcxx does not have a formal release mechanism. These are tags Apple has used for internal tagging. That being said, using the svn list -v command it appears that libcpp-31 is dated 2011-07-24 and RELEASE_30/final is dated 2011-11-28.
Churn on libcxx is very low for now, and I make a personal attempt to ensure that tip-of-trunk is always in a "shippable" state. If other platforms have the need to tag at certain times, I have no objection to that.
I am not familiar with the Linux port of libc++. However I'm aware that people have been working on it. Jeffrey Yasskin and Richard Smith are two likely suspects on this list which might have more information for you. 
The latest commit I see related to Linux is by Richard Smith: