Fix merge issues and new compiler complaints

src/engine_redistribute.c

@@ -1231,7 +1231,7 @@ void engine_redistribute(struct engine *e) {
   s->size_bparts = engine_redistribute_alloc_margin * nr_bparts_new;
 
   /* Sink particles. */
-  new_parts = engine_do_redistribute(
+  new_parts = engine_do_redistribute(e,
       "sinks", sink_counts, (char *)s->sinks, nr_sinks_new, sizeof(struct sink),
       sink_align, sink_mpi_type, nr_nodes, nodeID, e->syncredist);
   swift_free("sinks", s->sinks);

src/threadpool.c

@@ -499,7 +499,7 @@ void *threadpool_memcpy(struct threadpool *tp, void *dest, void *src,
   /* Need a number of pages per thread to be worth while. See:
    *   https://gitlab.cosma.dur.ac.uk/swift/swiftsim/-/merge_requests/1661
    */
-  if ((n < 8 * 4096 * tp->num_threads) || tp->num_threads < 8) {
+  if ((n < (size_t)(8 * 4096 * tp->num_threads)) || (tp->num_threads < 8)) {
     memcpy(dest, src, n);
   } else {
     /* Also we see most of the gains (80%) using less than the total number of