Rename `ht_foreach_func` to `mrb_hash_foreach_func`.
MODIFY
include/mruby/hash.h
include/mruby/hash.h
@@ -211,8 +211,8 @@ size_t mrb_gc_mark_hash_size(mrb_state*, struct RHash*);
void mrb_gc_free_hash(mrb_state*, struct RHash*);
/* return non zero to break the loop */
-typedef int (ht_foreach_func)(mrb_state *mrb, mrb_value key, mrb_value val, void *data);
-MRB_API void mrb_hash_foreach(mrb_state *mrb, struct RHash *hash, ht_foreach_func *func, void *p);
+typedef int (mrb_hash_foreach_func)(mrb_state *mrb, mrb_value key, mrb_value val, void *data);
+MRB_API void mrb_hash_foreach(mrb_state *mrb, struct RHash *hash, mrb_hash_foreach_func *func, void *p);
MRB_END_DECL

MODIFY
src/hash.c
src/hash.c
@@ -498,7 +498,7 @@ ht_del(mrb_state *mrb, htable *t, mrb_value key, mrb_value *vp)
/* Iterates over the hash table. */
static void
-ht_foreach(mrb_state *mrb, htable *t, ht_foreach_func *func, void *p)
+ht_foreach(mrb_state *mrb, htable *t, mrb_hash_foreach_func *func, void *p)
{
segment *seg;
mrb_int i;
@@ -521,7 +521,7 @@ ht_foreach(mrb_state *mrb, htable *t, ht_foreach_func *func, void *p)
/* Iterates over the hash table. */
MRB_API void
-mrb_hash_foreach(mrb_state *mrb, struct RHash *hash, ht_foreach_func *func, void *p)
+mrb_hash_foreach(mrb_state *mrb, struct RHash *hash, mrb_hash_foreach_func *func, void *p)
{
ht_foreach(mrb, hash->ht, func, p);
}

Rename `ht_foreach_func` to `mrb_hash_foreach_func`.