Build fix for libnss_db on glibc 2.3

[Daniel Jacobowitz <dan@debian.org>]

Here's a patch.  It works, too - it's running on voltaire with glibc 2.3.1
now.  This patch is _required_ to use libnss-db with glibc 2.3.1; should
glibc conflict with older versions of nss-db?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer