This should replace several "segfaults" and "illegal instruction" errors
with messages that contain a bit more context. I also put in a link to
the bug tracker to make users' lives a bit easier.
For context, `__builtin_unreachable`'s behavior is undefined and is
intended only as a mechanism to help the compiler see that code will not
return. I do still include it in the new code because if I don't,
compilation produces a lot more warnings as it can't see that
`NOT_IMPLEMENTED_YET` and `UNREACHABLE` cannot return.
- remove unused variables and class fields
- add support for gcc 4.5 & clang's __builtin_unreachable
- fix 2 bugs related to strict aliasing
- remove a few unused function parameters
Signed-off-by: Nuno Lopes <t-nclaud@microsoft.com>
