get_init_creds_opt extensibility

get_init_creds_opt extensibility

 r18922@cathode-dark-space:  coffman | 2006-12-04 18:30:15 -0500
 First cut at making the get_init_creds_opt structure extendable
 and adding library functions to set options for preauthentication
 plugins.

 This does *not* include a compatibility function to work like
 Heimdal's krb5_get_init_creds_opt_set_pkinit() function.

 Hopefully, the test code that doesn't belong in kinit.c is
 obvious.

 r18929@cathode-dark-space:  coffman | 2006-12-07 10:01:20 -0500
 Remove extra "user_id" parameter.

 Add function which duplicates the Heimdal interface (if we can agree on
 what the matching attribute names should be).

 r18934@cathode-dark-space:  coffman | 2006-12-08 15:28:03 -0500
 Update to use the simplified interface for krb5_get_init_creds_opt_set_pa()

 Add code in kinit to process "-X" options as preauth options and pass
 them along.

 r18936@cathode-dark-space:  coffman | 2006-12-11 12:04:26 -0500
 Move prototypes for get_init_creds_opt_get_pa() and
 krb5_get_init_creds_opt_free_pa() into the
 preauth_plugin.h header rather than krb5.hin.

ticket: new
status: open
component: krb5-libs

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19127 dc483132-0cff-0310-8789-dd5450dbe970