Fix: syscall list ioctl number conflict

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Expose lttng-modules ABI version ioctl

Check compatibility between lttng-modules and tools using a version
numbering specifically for the ABI, rather than relying on the major
version of lttng-modules per se. This takes into account that we
sometimes depend on lock-step updates of the toolchain, including tools
and modules.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>