This bug is related to this mailing list thread:
http://thread.gmane.org/gmane.linux.uml.user/5518
There are several people experiences linking failures
on 2.6.8.1 and earlier kernels, all with self-compiled
NPTL glibcs.
This bug is also tracked here:
http://bugs.gentoo.org/show_bug.cgi?id=49277