Merge branch 'sb/hashmap-cleanup'

Many uses of comparision callback function the hashmap API uses
cast the callback function type when registering it to
hashmap_init(), which defeats the compile time type checking when
the callback interface changes (e.g. gaining more parameters).
The callback implementations have been updated to take "void *"
pointers and cast them to the type they expect instead.

* sb/hashmap-cleanup:
  t/helper/test-hashmap: use custom data instead of duplicate cmp functions
  name-hash.c: drop hashmap_cmp_fn cast
  submodule-config.c: drop hashmap_cmp_fn cast
  remote.c: drop hashmap_cmp_fn cast
  patch-ids.c: drop hashmap_cmp_fn cast
  convert/sub-process: drop cast to hashmap_cmp_fn
  config.c: drop hashmap_cmp_fn cast
  builtin/describe: drop hashmap_cmp_fn cast
  builtin/difftool.c: drop hashmap_cmp_fn cast
  attr.c: drop hashmap_cmp_fn cast

config.c

@@ -1719,17 +1719,19 @@ static int configset_add_value(struct config_set *cs, const char *key, const cha
 }
 
 static int config_set_element_cmp(const void *unused_cmp_data,
-				  const struct config_set_element *e1,
-				  const struct config_set_element *e2,
+				  const void *entry,
+				  const void *entry_or_key,
 				  const void *unused_keydata)
 {
+	const struct config_set_element *e1 = entry;
+	const struct config_set_element *e2 = entry_or_key;
+
 	return strcmp(e1->key, e2->key);
 }
 
 void git_configset_init(struct config_set *cs)
 {
-	hashmap_init(&cs->config_hash, (hashmap_cmp_fn)config_set_element_cmp,
-		     NULL, 0);
+	hashmap_init(&cs->config_hash, config_set_element_cmp, NULL, 0);
 	cs->hash_initialized = 1;
 	cs->list.nr = 0;
 	cs->list.alloc = 0;