The call to `exception_warning` in `support.c` is now performed
directly by the `raise_exception_helper` function defined in
`support.c`, so that we can avoid calling two different functions in the
translated and isolated module.
In `support.c`, we employ `arch_prctl` to set the value of segment
registers. However glibc, despite providing that function, doesn't
provide its prototype in any header file. This commit declares it,
according to the declaration provided in the man page.
This commit moves around most files. The new directory structure is as
follows:
* `lib/$LIBRARY/`: contains a library, i.e., a set of `.cpp` files used
by multiple libraries/tools.
* `include/revng/$LIBRARY/`: contains the public headers associated to
the library in `lib/$LIBRARY/`.
* `tools/$TOOL/`: directory where all the `.cpp` files (and private
headers) for a tool reside. Currently we have two tools: `revamb` and
`revamb-dump`.
On top of this, all file names are now in camel case.