This commit addresses the following warning reported by clang, which
happens by default, as long as CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG is disabled:
warning: empty struct has size 0 in C, size 1 in C++
C and C++ must use the same size for objects to avoid corruption during run
time.
Fixes: 97e7e685bfcd ("mempool: add structure for object trailers")
Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>