compile fixes for !HAVE_GSS_USEROK and !HAVE_GSS_INDICATE_MECHS_BY_ATTRS

[jbasney]

Fixes for compiling against GSI GSSAPI which doesn't (yet) have gss_userok() or gss_indicate_mechs_by_attrs(). Needed so I can include support for generic GSS-API mechanisms in the GSI-OpenSSH code base (https://github.com/ncsa/gsi-openssh).

Compiler warnings/errors fixed are:

gss-serv.c:81:1: warning: unused function 'ssh_gssapi_generic_localname'
gss-serv.c:118:30: error: initializing 'const ssh_gssapi_mech' with an expression of incompatible type 'void *'
gss-serv.c:251:22: error: use of undeclared identifier 'GSS_C_MA_MECH_NEGO'
gss-serv.c:252:22: error: use of undeclared identifier 'GSS_C_MA_NOT_MECH'
gss-serv.c:253:22: error: use of undeclared identifier 'GSS_C_MA_DEPRECATED'
gss-serv.c:258:19: warning: implicit declaration of function 'gss_indicate_mechs_by_attrs'

[hartmans]

Any chance I could get you to submit this over at
https://github.com/gss-openssh?
Painless security is getting out of the openssh business and we're
trying to get an open-source group together to do that work.

[jbasney]

Yes, I'll try to submit it over at https://github.com/gss-openssh today.

[jbasney]

gss-openssh/openssh-portable#1 submitted. Since https://github.com/gss-openssh didn't already have SimonWilkinson#2 I submitted a pull request combining both.