Fix incorrect cast in minizip's ioapi.c.
diff --git a/contrib/minizip/ioapi.c b/contrib/minizip/ioapi.c
index baa6776..814a6fd 100644
--- a/contrib/minizip/ioapi.c
+++ b/contrib/minizip/ioapi.c
@@ -208,7 +208,7 @@
     }
     ret = 0;
 
-    if(FSEEKO_FUNC((FILE *)stream, (long)offset, fseek_origin) != 0)
+    if(FSEEKO_FUNC((FILE *)stream, (z_off_t)offset, fseek_origin) != 0)
                         ret = -1;
 
     return ret;