* check `ctx->gc_ctx` in `gss_inquire_context()`
* check `gm_inquire_cred != NULL` in `gss_inquire_context()`
* check `min_lifetime` in `gss_inquire_cred()`
* check `gm_inquire_cred_by_mech != NULL` in `gss_inquire_cred_by_mech()`
* set mech error in `gss_inquire_cred_by_oid()`
* don't clobber error in `gss_inquire_cred_by_oid()`
* don't pass NULL minor_status to `gss_krb5_free_lucid_sec_context()`
* allow NULL ccache in `gss_krb5_ccache_name()`
* NULL names OK in `_gss_find_mn()`
* allow empty names in `gss_import_name()` (removes `input_name_buffer` length
check). to support ANONYMOUS. in `gss_import_name()`, ignore mech name
import failure as long as it's possible to import the name in some other
mechanism
* better argument validation in `gss_export_sec_context()`
* in `gss_compare_name()`, check `mn2 != NULL`
* check `gss_add_oid_set_member()` return code in `gss_indicate_mechs()`
* in `gss_destroy_cred()`, set output cred handle to `GSS_C_NO_CREDENTIAL`
* cast size_t to OM_uint32 where required
Works for krb5 and SPNEGO mechanisms. Kerberos credentials are passed as
credential cache names, or if there are memory based credentials, inband in the protocol. This means that the credentials buffers must be keep secret.
As documented by IBM (they have the wrong prototype though)
and GGF (GSS-API Extensions) back in 2001
