the kernel uses long longs in the struct, but the documentation
says they're long. so we need to fixup the mismatch between the
userspace and kernelspace structs.
since the struct offers a mem_unit member, we can avoid truncation
by adjusting that value.
it's legal to call the __syscall functions with more arguments than
necessary, and the __syscall_cp cancel dummy impl. does just that.
thus we must insert the switch for all possible syscalls numbers
into all of the syscallN inline functions.
- the nanosleep fixup "fixed" the second timespec* argument erroneusly.
- the futex fixup was missing the check for FUTEX_WAIT.
- general cleanup using a macro.
