Use `mrb_int` instead of `int` as argument to `mrb_hash_new_capa`.
MODIFY
include/mruby/hash.h
include/mruby/hash.h
@@ -24,7 +24,7 @@ struct RHash {
#define mrb_hash_ptr(v) ((struct RHash*)(mrb_ptr(v)))
#define mrb_hash_value(p) mrb_obj_value((void*)(p))
-MRB_API mrb_value mrb_hash_new_capa(mrb_state*, int);
+MRB_API mrb_value mrb_hash_new_capa(mrb_state*, mrb_int);
/*
* Initializes a new hash.

MODIFY
src/hash.c
src/hash.c
@@ -140,7 +140,7 @@ mrb_gc_free_hash(mrb_state *mrb, struct RHash *hash)
MRB_API mrb_value
-mrb_hash_new_capa(mrb_state *mrb, int capa)
+mrb_hash_new_capa(mrb_state *mrb, mrb_int capa)
{
struct RHash *h;

Use `mrb_int` instead of `int` as argument to `mrb_hash_new_capa`.