r13248: Revert revision 13071. It turns out that sys/param.h can be implicitly

r13248: Revert revision 13071. It turns out that sys/param.h can be implicitly
included from other headers. In this case, undeffing MIN and MAX is a
really bad idea because the subsequent include of sys/param.h will do
nothing because of its include guards.
(This used to be commit 8aa8be93b09cfbd176455738dfd305047030fd50)