Use zip_XXX_t instead of struct zip_XXX or enum zip_XXX.

lib/zip_get_num_entries.c

diff --git a/lib/zip_get_num_entries.c b/lib/zip_get_num_entries.c
index 9a70375..c8644a4 100644
--- a/lib/zip_get_num_entries.c
+++ b/lib/zip_get_num_entries.c
@@ -36,7 +36,7 @@
 
 
 ZIP_EXTERN zip_int64_t
-zip_get_num_entries(struct zip *za, zip_flags_t flags)
+zip_get_num_entries(zip_t *za, zip_flags_t flags)
 {
     zip_uint64_t n;