Some problems presented by the implementation of NPTL. The package solution DOES backport upstream changes to use the new and better working NTPL library.
Known issues with disabling NPTL:
DB4 is hosed. Requires re-build without NPTL
A link to re-built packages will be made available on http://www.friocorte.com
If installing XEN-0 from source, best results come from using a stock kernel.org kernel tree.
Some kernel compiling tricks may be needed(manually creating an initrd for example)