--- netpbm/converter/other/Makefile.linkage~	2010-11-24 14:28:39.000000000 +0100
+++ netpbm/converter/other/Makefile	2010-11-24 14:30:41.453333120 +0100
@@ -156,7 +156,7 @@ tifftopnm pamtotiff pnmtotiffcmyk: %: %.
 ifeq ($(shell libpng$(PNGVER)-config --version),)
   PNGLIB_LIBOPTS = $(shell $(LIBOPT) $(LIBOPTR) $(PNGLIB) $(ZLIB))
 else
-  PNGLIB_LIBOPTS = $(shell libpng$(PNGVER)-config --ldflags)
+  PNGLIB_LIBOPTS = $(shell libpng$(PNGVER)-config --ldflags) -lz
 endif
 
 pngtopam: %: %.o pngx.o $(NETPBMLIB) $(LIBOPT)