kerberos libraries were not linked properly (missing dependencies),
which causes 3rd party applications linking to fail when --as-needed
ld flag is used. I also added the --no-undefined ld(1) flag to make
sure that there're no missing dependencies.
MFC after: 3 days
similar the the Solaris implementation. Repackage the krb5 GSS mechanism
as a plugin library for the new implementation. This also includes a
comprehensive set of manpages for the GSS-API functions with text mostly
taken from the RFC.
Reviewed by: Love Hörnquist Åstrand <lha@it.su.se>, ru (build system), des (openssh parts)