When a function in the BPF program starts with "tracepoint__", parse
the rest of the name as a tracepoint category and name and attach the
tracepoint automatically. For example:

```
int tracepoint__sched__sched_switch(...)
```

As a result, the sched:sched_switch tracepoint is enabled and the function
is attached to that tracepoint.

When a probe function refers to a tracepoint arguments structure,
such as `struct tracepoint__irq__irq_handler_entry`, add that structure
on-the-fly using a Clang frontend action that runs before any other
steps take place.

Typically, the user will create tracepoint probe functions using
the TRACEPOINT_PROBE macro, which avoids the need for specifying
the tracepoint category and event twice in the signature of the
probe function.

Older versions of GCC don't support std::regex even though they support
most of C++11. To avoid breaking the build on older systems, such as
Ubuntu 14.04, use manual parsing instead of std::regex.