Add comment to gp_rpc.x explaining its origin and purpose
Untangle gssx_cred/context/handle
Fix typo (s/CONTECT/CONTEXT)
Fix error that made credential handles not an array of elements
Use correct type for exported context

gss_export_context() returns a gss_buffer_t, so match it in the gssx_ctx
structure by using the correlated gssx_buffer type instead of octet_string.
Update gss_proxy generated files after .x file changes
Refactor gp_rpc_process

Remove useless context abstraction for calls and replies.
Add basic configure test for gssapi library
Add gssx conversion functions
Add functions to export/import credentials

This is a temporary quick and simple implementation to proceed with
prototyping, it will be later replaced with a correct implementation.
Add accept_sec_context implementation
Add test program to exercise accept_sec_context
Improve test program

Split it into a lcient and a server thread.
Properly implement gss_init_sec_context loop for the client part.
Still relies on kerberos being used and gss_accept_sec_context beeing finished
in one roundtrip.
Fix gssx_handle, no need for an array of creds, just 1
Regenerate rpcgen files after gss_proxy.x fixes
Use the gp_rpc prefix for files that implement the rpc interface
Move includes in gp_rpc_process.h

This way it is easier to have the right includes in all gp_rpc_* files.
Shorten gp_rpc_arg/res unions member names

We do not need long redundant name for the union members.
Shortening makes it easier to read and follow code.
Add helper to return status from rpc functions
Add a function to find credential handles