x86 x32 system calls are not supported by LTTng. They are currently not
traced simply because their system call number is beyond the range of
NR_compat_syscalls.
However, this mostly happens by accident rather than by design.
Enforce this with an explicit check for in_x32_syscall(), which clearly
documents that those are not supported.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3a6985a8355f14f4e557ee7f5edea36969dadfe9