upgraded to zlib 1.2.1
diff --git a/win32/Makefile.mingw b/win32/Makefile.mingw
index a0fb33c..415620c 100644
--- a/win32/Makefile.mingw
+++ b/win32/Makefile.mingw
@@ -79,7 +79,7 @@
 LIBS += -liconv
 endif 
 ifeq ($(WITH_ZLIB),1)
-LIBS += -lzlib
+LIBS += -lzdll
 endif
 ifeq ($(WITH_THREADS),posix)
 LIBS += -lpthreadGC