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

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.

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;