 Cannot enable libmemcached protocol

I have `libmemcached-dev` installed (latest version) and when I run `pecl install memcached`

I'm getting:
```
checking for memcached protocol support... enabled
checking whether libmemcachedprotocol is usable... no
configure: error: Cannot enable libmemcached protocol
```

With `3.0.4` works fine.