More MAC-building infrastructure.

We need more infrastructure to make the MAC framework code compile in userspace.
Reinstate ClangTool workaround.

Others won't have my Clang patches installed...
$^ means "all inputs", not $<.
MAC framework's TESLA assertion.

This assertion detects that we've failed to set the correct auditing flags before calling namei().
Ignore some things.
Prettify demo output.

Make the various steps of the demo (compilation vs running) a little clearer.
Add missing certificate files.

The demo needs these to run!