Use zip_XXX_t instead of struct zip_XXX or enum zip_XXX.
diff --git a/lib/zip_discard.c b/lib/zip_discard.c
index 2ca11df..db22370 100644
--- a/lib/zip_discard.c
+++ b/lib/zip_discard.c
@@ -42,7 +42,7 @@
    corresponding file. */
 
 void
-zip_discard(struct zip *za)
+zip_discard(zip_t *za)
 {
     zip_uint64_t i;