string.c: remove two unused functions.

* `mrb_cstr_to_inum()`
* `mrb_cstr_to_dbl()`

include/mruby/string.h

@@ -370,9 +370,7 @@ MRB_API mrb_value mrb_str_dup(mrb_state *mrb, mrb_value str);
 MRB_API mrb_value mrb_str_intern(mrb_state *mrb, mrb_value self);
 
 MRB_API mrb_value mrb_str_to_inum(mrb_state *mrb, mrb_value str, mrb_int base, mrb_bool badcheck);
-MRB_API mrb_value mrb_cstr_to_inum(mrb_state *mrb, const char *s, mrb_int base, mrb_bool badcheck);
 MRB_API double mrb_str_to_dbl(mrb_state *mrb, mrb_value str, mrb_bool badcheck);
-MRB_API double mrb_cstr_to_dbl(mrb_state *mrb, const char *s, mrb_bool badcheck);
 
 /**
  * Returns a converted string type.

src/string.c

@@ -2363,12 +2363,6 @@ mrb_str_len_to_inum(mrb_state *mrb, const char *str, size_t len, mrb_int base, i
   return mrb_fixnum_value(0);
 }
 
-MRB_API mrb_value
-mrb_cstr_to_inum(mrb_state *mrb, const char *str, mrb_int base, mrb_bool badcheck)
-{
-  return mrb_str_len_to_inum(mrb, str, strlen(str), base, badcheck);
-}
-
 /* obslete: use RSTRING_CSTR() or mrb_string_cstr() */
 MRB_API const char*
 mrb_string_value_cstr(mrb_state *mrb, mrb_value *ptr)
@@ -2535,12 +2529,6 @@ bad:
   return d;
 }
 
-MRB_API double
-mrb_cstr_to_dbl(mrb_state *mrb, const char *s, mrb_bool badcheck)
-{
-  return mrb_str_len_to_dbl(mrb, s, strlen(s), badcheck);
-}
-
 MRB_API double
 mrb_str_to_dbl(mrb_state *mrb, mrb_value str, mrb_bool badcheck)
 {