[cfe-users] libcxx.llvm.org linux build instructions unclear

[Larry Evans]

The instructions on:
   http://libcxx.llvm.org/
say:
    We can now run CMake:

     CC=clang CXX=clang++ cmake -G "Unix Makefiles" 
-DLIBCXX_CXX_ABI=libstdc++ 
-DLIBCXX_LIBSUPCXX_INCLUDE_PATHS="/usr/include/c++/4.7/;/usr/include/c++/4.7/x86_64-linux-gnu/" 
-DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr <libc++-source-dir>

however, it does not say what to put for <libc++-source-dir>
or in which directory this command is to be run.  One might
guess this command is to be run inb the directory where the buildit
script is located, because that's what the earlier instructions
(for Mac OS) were run from; however, that's not at all clear.

Any help appreciated.

-regards,
Larry