[$] Maximal min() and max()

Like many projects written in C, the kernel makes extensive use of the Cpreprocessor; indeed, the kernel's use is rather more extensive than most.The preprocessor famously has a number of sharp edges associated with it.One might not normally think of increased compilation time as one of them,though. It turns out that some changes to a couple of conceptually simplepreprocessor macros - min() and max() - led to some trulypathological, but hidden, behavior where those macros were used.