http://libcxx.llvm.org/
http://gcc.gnu.org/libstdc++/
https://github.com/pathscale/libcxxrt
https://github.com/pathscale/libunwind
http://wiki.osdev.org/Libsupcxx
http://libcxxabi.llvm.org/
libgcc_s
http://compiler-rt.llvm.org/
http://www.gnu.org/software/libc/

My thread: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2012-March/020040.html

Other thread: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2012-July/022781.html

  I've written some documentation on the transition in FreeBSD here:
  http://wiki.freebsd.org/NewC++Stack
  
  Slides from my FOSDEM presentation:
  https://archive.fosdem.org/2012/schedule/event/399/108_BSDC++.pdf
  
  Howard's excellent talk about libc++:
  http://www.llvm.org/devmtg/2010-11/Hinnant-libcxx.pdf