[xml] problem with compiling libxml2 on RHEL5.3

[Chuck White <chuckwhite8 charter net>]

Hello -- while I compile libxml2-2.7.8 on a RHEL5.3 x86_64 box, I am 
getting the following error

        ./.libs/libxml2.so: undefined reference to `gzopen64'

Here are the steps I have followes to build zlib. I used the 
instructions on the following page
http://www.linuxfromscratch.org/lfs/view/development/chapter06/zlib.html
    ================
    LIBZ=zlib-1.2.5
    tar xzf bin/$LIBZ.tar.gz
    cd $LIBZ
    sed -i 's/ifdef _LARGEFILE64_SOURCE/ifndef _LARGEFILE64_SOURCE/' 
zlib.h
    CFLAGS='-mstackrealign -fPIC -O3'
    ./configure --libdir=/usr/local/lib64 1>"$LIBZ"_cfg.log 2>&1
    make 1>"$LIBZ"_mk.log 2>&1
    sudo make install 1>"$LIBZ"_inst.log 2>&1
    ================

I am using the following steps to build libxml2
    ================
    LIBXML=libxml2-2.7.8
    tar xzf bin/$LIBXML.tar.gz
    cd $LIBXML
    ./configure --with-zlib=/usr/local --libdir=/usr/local/lib64 
1>"$LIBXML"_cfg.log 2>&1
    make 1>"$LIBXML"_mk.log 2>&1
    sudo make install 1>"$LIBXML"_inst.log 2>&1
    ================

Looking at this post 
http://mail.gnome.org/archives/xml/2010-October/msg00072.html, I 
searched for zlib.h
(sudo find / -name "zlib.h" -ls) and found
    79565 Jan  3 00:21 /usr/local/include/zlib.h
    66188 Jul 19  2006 /usr/include/zlib.h
I am trying to use the version of zlib.h which is in /usr/local/include. 
The corresponding library is in
    106903 Jan  3 00:21 /usr/local/lib64/libz.so.1.2.5

Are there any other arguments I need to set?  Or, changes I need to 
make?  Thanks.