Comment # 2 on bug 1037033 from Michal Nowak

Created attachment 724333 [details]
VNC extension pack build

Hi Larry, thanks for looking into this. Attaching a raw patch which works for
me. 

The important part is "build VNC extension pack" hunk.

Notably RPM sub-package's `%post vnc` is wrong, but I am not sure how to fix
this one, and autoacceptance of license did not work for me as well.

What it does:

1. Forces tar run with format set to 'gnu'. We seems to default to 'posix', but
VirtualBox does not support this format.
2. Builds the extension.
3. Installs extension pack to the right place.
4. Installs license which is required for automated acceptance in `%post vnc`.

Let me know if this approach makes the extension pack build for you as well.