--- a/configure.ac
+++ b/configure.ac
@@ -244,7 +244,7 @@ dnl (PNG page export)
 dnl
 HAVE_PNG="yes"
 AC_CHECK_LIB(png, png_destroy_write_struct,
-  LIBS="$LIBS -lpng -lz", HAVE_PNG="no", -lz -lm)
+  LIBS="-lpng $LIBS -lz -lm", HAVE_PNG="no", -lz -lm)
 if test "x$HAVE_PNG" = xyes; then
   AC_DEFINE(HAVE_LIBPNG, 1, [Define if you have libpng])
 fi
