debuild of evolution-data-server fails

["John A. Sullivan III" <jsullivan@opensourcedevel.com>]

Hello, all. We are trying to rebuild the evolution-data-server package
after patching it to hopefully end our current email nightmare.  The
base system is Lenny but we are using evolution from squeeze.  When I
try to debuild, I am getting the following errors:

checking for GNOME_PLATFORM... configure: error: Package requirements
(glib-2.0 >= 2.16.1
        gtk+-2.0 >= 2.14.0
        ORBit-2.0 >= 2.9.8
        libbonobo-2.0 >= 2.20.3
        gconf-2.0 >= 2.0.0
        libglade-2.0 >= 2.0.0
        libxml-2.0 >= 2.0.0
        libsoup-2.4 >= 2.3.0) were not met:

Package zlib was not found in the pkg-config search path.
Perhaps you should add the directory containing `zlib.pc'
to the PKG_CONFIG_PATH environment variable
Package 'zlib', required by 'GnuTLS', not found

zlib is installed. I did not check all the listed packages but the ones
I checked were installed with the latest versions.  My command sequence
was:

apt-get -t testing source evolution-data-server (as non-root)
apt-get -t testing build-dep evolution-data-server (as root)
patched evolution-data-server
edited debian/changelog and debian/rules (disabled gnome-key-ring - also
tried it with this enabled as per the default)
debuild -uc -us

What am I doing wrong? We are rather desperate to get this running.
Thanks - John