--- pngcheck-2.3.0.old/Makefile.unx
+++ pngcheck-2.3.0/Makefile.unx
@@ -18,10 +18,8 @@
 
 # macros --------------------------------------------------------------------
 
-ZPATH = ../zlib
-ZINC = -I$(ZPATH)
-#ZLIB = -L$(ZPATH) -lz
-ZLIB = $(ZPATH)/libz.a
+ZINC = -I/usr/local/include
+ZLIB = -L/usr/local/lib -lz
 
 INCS = $(ZINC)
 LIBS = $(ZLIB)