can't build test library on OS X

[lucy:~/Desktop/uffi/tests] desoi% make mac
cc -dynamic -c uffi-c-test-lib.c -o uffi-c-test-lib.o
ld -bundle /usr/lib/bundle1.o -flat_namespace -undefined suppress -o 
uffi-c-test-lib.dylib uffi-c-test-lib.o
ld -bundle /usr/lib/bundle1.o -flat_namespace -undefined suppress 
/usr/lib/libz.dylib -o z.dylib
ld: /usr/lib/libz.dylib load command 8 unknown cmd field
make: *** [mac] Error 1


????


John DeSoi, Ph.D.