patch 8.1.1219: not checking for NULL return from alloc()

Problem:    Not checking for NULL return from alloc().
Solution:   Add checks. (Martin Kunev, closes #4303, closes #4174)
diff --git a/src/proto/crypt_zip.pro b/src/proto/crypt_zip.pro
index 74784e1..868b131 100644
--- a/src/proto/crypt_zip.pro
+++ b/src/proto/crypt_zip.pro
@@ -1,5 +1,5 @@
 /* crypt_zip.c */
-void crypt_zip_init(cryptstate_T *state, char_u *key, char_u *salt, int salt_len, char_u *seed, int seed_len);
+int crypt_zip_init(cryptstate_T *state, char_u *key, char_u *salt, int salt_len, char_u *seed, int seed_len);
 void crypt_zip_encode(cryptstate_T *state, char_u *from, size_t len, char_u *to);
 void crypt_zip_decode(cryptstate_T *state, char_u *from, size_t len, char_u *to);
 /* vim: set ft=c : */