This new version works with all compiler versions, and also catches the
case where somebody tries to pass in an array as an argument to the
ioctl macros.  Thus we verify that only proper types are used.

I have checked now that the object code for arch/s390/kernel/compat_ioctl.o
remains identical and that the whole kernel compiles for s390 and i386,
after fixing the broken ioctl numbers.