Add tests for gss_inquire_mechs_for_name
Simplify gss_inquire_mechs_for_name

Use gss_indicate_mechs instead of gssint_get_mechanisms and
gssint_mech_to_oid to iterate over the list of mechanism OIDs.  Use a
static helper to determine whether a mech supports a name type,
avoiding most of the work done in the for loop.  Use a cleanup
handler.  Don't leave partial results in the output parameter on
error.
Delete unused internal mechglue functions

Get rid of gssint_get_mechanisms, gssint_mech_to_oid, and
gssint_oid_to_mech, which constructed a list of mechanism names and
mapped between mech names and OIDs.  These functions were only used by
gss_inquire_mechs_for_name, which now uses gss_indicate_mechs instead.
Fix a typo
Add an input ccache get-init-creds option

Add a krb5_get_init_creds_opt_set_in_ccache() function.  An input
ccache may hold configuration data which the client libraries can
use to influence their decisions.
Use octal escapes for non-printable parts of {str}/{lenstr}/{data}

When adding {str}, {lenstr}, or {data} to trace output, scan for
bytes which might be non-printable, and add them as octal-escaped
versions of themselves if any are found.
Add a -C flag to dump configuration entries
Add "pa_types" configuration to ccaches

* When producing preauth data, keep track of the types of padata which
  the module that produced the data can handle.  Originally this was
  just the type of data we'd produced, but that caused problems for
  PKINIT.
* After obtaining credentials, store that list of preauth types as a
  "pa_types" configuration item in the out_ccache.
* Read a list of allowed preauth types from an in_ccache, if possible.
* If we have a list of allowed preauth types, skip any "real" modules
  which aren't in that list.
Add "pa_config_data" configuration to ccaches

* Read a "pa_config_data" item from an in_ccache, if provided, and add a
  callback which client preauth plugins can use to retrieve a data item
  that's indexed and stored as a preauth data item (krb5_pa_data *).
* Add a callback which client preauth plugins can use to provide a data
  item, formatted as a preauth data item (krb5_data + preauth type), and
  store them in the out_ccache, if possible.
Misc fixes for anonymity and crypto agility

* Agility fix: don't try to free an uninitialized keyblock.
* Anonymity: don't try to sign data when we have no signer specified,
  and don't try to add signed attributes then, either.  Don't bail on
  unsigned data: just note that it's not signed, since that's expected
  now, and carry on.
* Reset the prompt_types list immediately after the prompter callback
  returns, as is done elsewhere.
* Use a temporary variable to hold the chain-inclusion setting for CMS.
* Whitespace tweaks.
* Print a debug message if we're unable to locate the matching private
  key for a certificate when we've just loaded both of them from PEM
  files.
Use config storage for client identity selection

* Keep track of the names of client identities when we load them.
* Store the client identity we just used when we create or retry a
  client request.
* If we read a client identity from the configuration, treat it like the
  KDC does: pick the "this is it, there is no other" branch.