Fix FTBFS with GCC 12 on ppc64el
Fix FTBFS with GCC 12 on ppc64el

GCC 12 on ppc64el complains about "key" being undefined on testapp.c.
This commit silences the error.

Signed-off-by: Sergio Durigan Junior <a5f45bda81ce6df9d35e01e62d1f94d5631db67f@sergiodj.net>

memcached/memcached,memcached/memcached,dormando/memcached,dormando/memcached,memcached/memcached,dormando/memcached,dormando/memcached,dormando/memcached,memcached/memcached,memcached/memcached