Add a few more headers required by getaddrinfo(3).

Follow-up to cbb7f57; the code built on Linux despite the lack of required
includes most likely because netdb.h ends up indirectly including
sys/types.h and sys/socket.h.

client_machine.cpp

@@ -28,6 +28,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <QFutureWatcher>
 // system
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
 #include <netdb.h>
 
 namespace KWin {

tests/test_client_machine.cpp

@@ -28,6 +28,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <xcb/xcb.h>
 // system
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
 #include <netdb.h>
 
 namespace KWin {