tree-wide: add missing includes

Add a few includes that we rely on to be include already.

src/libsystemd/sd-bus/bus-bloom.h

@@ -22,6 +22,7 @@
 ***/
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
 /*

src/libsystemd/sd-netlink/netlink-types.h

@@ -21,6 +21,8 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include "macro.h"
+
 enum {
         NETLINK_TYPE_UNSPEC,
         NETLINK_TYPE_U8,                        /* NLA_U8 */