These are currently only run by the new DOIT3 test-running script.
Note that these tests are designed to be applicable to most implementations of C95/C99/C11, not just ORCA/C. They do make certain assumptions not guaranteed by the standards (e.g. power of 2 types and some properties of IEEE-like FP), but in general those assumptions should be true for most 'normal' systems.
It was calling fabs() without having included <math.h>, causing fabs() to be treated as returning an int rather than a floating-point value. This misinterpretation of the return value could cause test failures.
These involve recent standards-conformance patches for printf and scanf, which changed some (non-standard) behaviors that the test cases were expecting.
I also fixed a couple things that clang flagged as undefined behavior, even though they weren't really causing problems under ORCA/C.
