Compiling libcxx without changes to the system dirs

Hi All,
   I'm trying to replace libstdc++ with libcxx in our project. I read the instructions provided at libcxx home page.
   I found that I dont need to copy the headers (cxxabi.h, bits/cxxabi_tweaks.h, cxxabi-forced.h) from /usr/include/c++/4.5/... to /usr/local/include/... . I copied the files to a folder and included that in the compilation of the libcxx sources.
   I also found that I didnt need to copy the* to /usr/lib, I didnt need to create the /usr/include/c++/v1 softlink pointing to libcxx/include. I got around by including the libcxx/include in the header path (-I..libcxx/include) and libcxx/lib path in the lib path (-L...libcxx/lib).

   I had to set HEADER_INCLUDE=...libcxx/include and SOURCE_LIB=...libcxx/lib before invoking testit.This way I got around making any changes to the system dirs to use libcxx.

   Do you see any obvious mistakes above?