According to C standard the size of a structure without fields is
not defined (see
https://stackoverflow.com/questions/21851930/size-of-empty-structure-in-c-and-c).
As we almost only use GCC currently these structures are of size 0.
This can became a problem if 2 sides talking a given protocol use
these structures.
To avoid such possible mismatch (for instance having one side C and
the other C++ which defines these structures as having 1 as size) add
an empty (0-size array) field.
Although a 0-size array is not considered also that portable we use
extensively this feature with different compilers never encountering
issues.
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Uri Lublin <uril@redhat.com>