Add sufficient coccinelle tooling to run coccinelle without stress

I think we need two pieces of coccinelle tooling to be able to use it effectively:

1. A script that tells us which files have parsing problems.

2. A script to invoke spatch with the right arguments.

Based on 1 and 2, we can improve our tor-coccinelle.h file to handle more of our codebase, and we can apply coccinelle scripts without trying to remember the name of the "-macro-file-builtins" flag.