pull up r19127 from trunk

pull up r19127 from trunk

 r19127@cathode-dark-space:  tlyu | 2007-01-30 16:38:47 -0500
 ticket: new
 status: open
 subject: get_init_creds_opt extensibility
 component: krb5-libs

  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: 5420
status: open

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-6@19145 dc483132-0cff-0310-8789-dd5450dbe970