* Set argv[argc] to NULL when calling main
ISO C states that argv[argc] shall be a null pointer.
The OpenSSH codebase does not appear to rely on this currently, but
better to be safe in case something changes.
* Check for malloc failure in sshd wmain
1. Deploy the key files to separate folder to avoid overwriting.
2. Enable hostkeys and kex unit tests.
3. Generate debug info in pdb
4. minor update on snmprintf
AF_UNIX kind of sockets are now supported. socket() and connect() calls are implemented. Windows specific logic in authfd.c is now removed. https://github.com/PowerShell/Win32-OpenSSH/issues/532 is created to keep track of ssh-agent end point authentication
