diff --git a/contrib/minizip/crypt.h b/contrib/minizip/crypt.h
index 9da1537..1cc41f1 100644
--- a/contrib/minizip/crypt.h
+++ b/contrib/minizip/crypt.h
@@ -85,7 +85,7 @@
 #define RAND_HEAD_LEN  12
    /* "last resort" source for second part of crypt seed pattern */
 #  ifndef ZCR_SEED2
-#    define ZCR_SEED2 3141592654L       /* use PI as default pattern */
+#    define ZCR_SEED2 3141592654UL      /* use PI as default pattern */
 #  endif
 
 static unsigned crypthead(const char* passwd,       /* password string */