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

builtin/describe.c

@@ -55,10 +55,13 @@ static const char *prio_names[] = {
 };
 
 static int commit_name_cmp(const void *unused_cmp_data,
-			   const struct commit_name *cn1,
-			   const struct commit_name *cn2,
+			   const void *entry,
+			   const void *entry_or_key,
 			   const void *peeled)
 {
+	const struct commit_name *cn1 = entry;
+	const struct commit_name *cn2 = entry_or_key;
+
 	return oidcmp(&cn1->peeled, peeled ? peeled : &cn2->peeled);
 }
 
@@ -503,7 +506,7 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
 		return cmd_name_rev(args.argc, args.argv, prefix);
 	}
 
-	hashmap_init(&names, (hashmap_cmp_fn) commit_name_cmp, NULL, 0);
+	hashmap_init(&names, commit_name_cmp, NULL, 0);
 	for_each_rawref(get_name, NULL);
 	if (!names.size && !always)
 		die(_("No names found, cannot describe anything."));