remap mechanism-specific status codes in mechglue/spnego

remap mechanism-specific status codes in mechglue/spnego

This patch creates a mapping in the mechglue/spnego code to modify
mechanism status codes when passing them back to the application, so
that mechglue's display_status dispatcher can determine the correct
mechanism to dispatch to.

This is part of the "get enhanced error messages from gssapi
applications" project; ticket 5590 has updates to the Kerberos 5
mechanism to extract enhanced error messages (when there are any) from
the Kerberos library.

util/gen.pl, util/t_*.pm: New code generation script and templates.

lib/gssapi/generic: Add a new, global mapping that enumerates the
{mechOID,status} pairs as they're seen, allowing a magic mechOID value
to indicate com_err error codes from mechglue and spnego, and
reserving status code 0 for unknown errors.  Preload the Kerberos
"wrong principal" error code once for each mechanism OID used for
Kerberos, so the entries get fixed positions (1-3) in the table.

lib/gssapi/gss_libinit.c: Call the initializer and destructor
functions.

lib/gssapi/mechglue, lib/gssapi/spnego: Enter all mechanism-generated
or locally-generated status codes into the mapping table, and return
the table index to the application.  Do the reverse in display_status,
to get the messages from the mechanism..

lib/rpc: Define new function gssrpcint_printf to use for debugging
instead of printf, to redirect output away from dejagnu; add a couple
more debugging calls.  Check for minor status codes 1-3 now instead of
KRB5KRB_AP_WRONG_PRINC.

tests/dejagnu/krb-standalone/gssftp.exp: Test getting more detailed
error messages back, by having the ftp client attempt to authenticate
to a non-existent service, and examining the error message for the
service principal name.

ticket: new

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19831 dc483132-0cff-0310-8789-dd5450dbe970