librpc:ndr: Introduce ‘libndr_flags’ type

librpc:ndr: Introduce ‘libndr_flags’ type

The LIBNDR_FLAG_ namespace is getting dangerously full, with only a
single flag value (1 << 9) remaining for use. After that flag is put
into use, we won’t be able to add any new flags without increasing the
flag width to 64‐bit.

Up to now we’ve used a haphazard mix of int, unsigned, and uint32_t to
store these flags. Introduce a new type, ‘libndr_flags’, to be used
consistently to hold LIBNDR flags. If in the future we find we need to
move to 64‐bit flags, this type gives us an opportunity to do that.

Bump the NDR version to 4.0.0 — an major version increment, for we’re
changing the function ABI and adding the new symbol
ndr_print_libndr_flags.

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>