conf.CHECK_VARIABLE('KV5M_KEYTAB', headers='krb5.h', lib='krb5')
conf.CHECK_VARIABLE('KRB5_KU_OTHER_CKSUM', headers='krb5.h', lib='krb5')
conf.CHECK_VARIABLE('KRB5_KEYUSAGE_APP_DATA_CKSUM', headers='krb5.h', lib='krb5')
-conf.CHECK_VARIABLE('ENCTYPE_AES128_CTS_HMAC_SHA1_96', headers='krb5.h', lib='krb5')
-conf.CHECK_VARIABLE('ENCTYPE_AES256_CTS_HMAC_SHA1_96', headers='krb5.h', lib='krb5')
+conf.CHECK_VARIABLE('ENCTYPE_AES128_CTS_HMAC_SHA1_96', headers='krb5.h', lib='krb5', mandatory=True)
+conf.CHECK_VARIABLE('ENCTYPE_AES256_CTS_HMAC_SHA1_96', headers='krb5.h', lib='krb5', mandatory=True)
conf.CHECK_DECLS('KRB5_PDU_NONE', reverse=True, headers='krb5.h', lib='krb5')
conf.CHECK_STRUCTURE_MEMBER('krb5_keytab_entry', 'key',
headers='krb5.h',