Mostly from the use of ssize_t which does not play well with printf and
32bit arches on LK for underlying type reasons that haven't really ever
been sorted out properly.
Two handlers accidentally had the wrong prototype, called the wrong
thing and/or had the wrong name.
Should only affect divrem_overflow_abort, negate_overflow_abort.
Add an UBSAN implementation and a new UBSAN switch to the make build.
The implementation is taken from Onyx and handles most of the cases
that should be needed for a kernel build. Floating point and fancy
C++ CFI features are not supported yet.
To build with UBSAN, pass UBSAN=1 to make such as:
PROJECT=pc-x86-64-test make -jN UBSAN=1
