This is more of what we want to be doing anyway, we don't care about all
the forks in existence.
Additionally, include the comm[] with the pid so that instruments can take
action based on it.
This brings together the two libraries back into one now that the whole
design is pretty well sorted out. They depend on roughly the same libraries
anyway and it's way easier of the single library can both read and write
the capture files (along with bringing in libsysprof-capture symbols in
a single place).
