Compile error for 2.1 on Solaris 2.7

I'm trying to compile Amaya 2.1 on a Sun running Solaris 2.7.  
I have had no problems compiling the previous versions.

In a directory called sun under the main Amaya directory, I did a 
"../configure --prefix=/devel/local" with no errors.

make all chugs along until:

make[3]: Entering directory `/devel/local/w3c/Amaya/sun/libwww/Library/src'

It then compiles several of the libraries OK, but finally chokes:

/bin/sh ../../libtool --mode=compile gcc -DHAVE_CONFIG_H -I.
-I../../../../../libwww/Library/src -I../.. -I/usr/local/include
-I../../../../../libwww/modules/md5
-I../../../../../libwww/modules/expat/xmlparse
-DW3C_ICONS=\"/usr/local/share/w3c-libwww\"  -O2 -W  -c
../../../../../libwww/Library/src/HTZip.c
gcc -DHAVE_CONFIG_H -I. -I../../../../../libwww/Library/src -I../..
-I/usr/local/include -I../../../../../libwww/modules/md5
-I../../../../../libwww/modules/expat/xmlparse
-DW3C_ICONS=\"/usr/local/share/w3c-libwww\" -O2 -W -Wp,-MD,.deps/HTZip.pp -c
../../../../../libwww/Library/src/HTZip.c -o HTZip.o
../../../../../libwww/Library/src/HTZip.c:23: zlib.h: No such file or
directory
make[3]: *** [HTZip.lo] Error 1
make[3]: Leaving directory `/devel/local/w3c/Amaya/sun/libwww/Library/src'
make[2]: *** [libwww] Error 2
make[2]: Leaving directory `/devel/local/w3c/Amaya/sun'
make[1]: *** [../libwwwapp.a] Error 2
make[1]: Leaving directory `/devel/local/w3c/Amaya/sun/amaya'

zlib.h is in Amaya/libpng/zlib, and there seem to be references to zlib in
the main Makefile, but it doesn't seem to be propagating the complete
include list.  Copying *.h from Amaya/libpng/zlib to Amaya/libwww
seems to be a dirty workaround.  Any suggestions as to the correct
correction?

Thanks

Jack Ostroff
jack_h_ostroff@groton.pfizer.com