Update function prototype regex

[ethandav]

https://regexr.com/40217

[pbrubaker]

You will want to run this on the current stdib file here.

[pbrubaker]

We will need to run the preprocessor on the file as there are macro definitions that create functions. Also omit any functions that start with __. We should just create a script that does this automatically - so there's a process in the future. Also document this in the readme.

[pbrubaker]

The most up to date regex is here.

https://regexr.com/4jaft