--- pngcrush-1.8.13/zutil.h.orig	2018-05-28 19:28:29.732393494 +0200
+++ pngcrush-1.8.13/zutil.h	2018-05-28 19:30:17.195725592 +0200
@@ -29,10 +29,6 @@
 #  include <stdlib.h>
 #endif
 
-#ifdef Z_SOLO
-   typedef long ptrdiff_t;  /* guess -- will be caught if guess is wrong */
-#endif
-
 #ifndef local
 #  define local static
 #endif