Add scan target functions for presym

Add the following functions:

- mrb_intern_cstr
- mrb_define_singleton_method
- mrb_define_class_under
- mrb_define_module_under

include/mruby/presym.h

@@ -29,8 +29,8 @@
  *   MRB_SYM(xor)    //=> xor    (Word characters)
  *
  * For `MRB_OPSYM`, specify the names corresponding to operators (see
- * `MRuby::Presym::OPERATORS` in `lib/mruby/presym.rb for the names that can
- * be specified for it). Other than that, describe only word characters
+ * `MRuby::Presym::OPERATORS` in `lib/mruby/presym.rb` for the names that
+ * can be specified for it). Other than that, describe only word characters
  * excluding leading and ending punctuations.
  *
  * These macros are expanded to `mrb_intern_lit` if presym is disabled,

include/mruby/presym/scanning.h

@@ -11,14 +11,19 @@
 
 #undef mrb_intern_lit
 #define mrb_intern_lit(mrb, name) MRB_PRESYM_SCANNING_TAGGED(name)
+#define mrb_intern_cstr(mrb, name) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_method(mrb, c, name, f, a) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_class_method(mrb, c, name, f, a) MRB_PRESYM_SCANNING_TAGGED(name)
+#define mrb_define_singleton_method(mrb, c, name, f, a) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_class(mrb, name, s) MRB_PRESYM_SCANNING_TAGGED(name)
+#define mrb_define_class_under(mrb, o, name, s) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_module(mrb, name) MRB_PRESYM_SCANNING_TAGGED(name)
+#define mrb_define_module_under(mrb, o, name) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_module_function(mrb, c, name, f, s) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_const(mrb, c, name, v) MRB_PRESYM_SCANNING_TAGGED(name)
 #define mrb_define_global_const(mrb, name, v) MRB_PRESYM_SCANNING_TAGGED(name)
 
+
 #define MRB_OPSYM(name) MRB_OPSYM__##name(mrb)
 #define MRB_CVSYM(name) MRB_PRESYM_SCANNING_TAGGED("@@" #name)
 #define MRB_IVSYM(name) MRB_PRESYM_SCANNING_TAGGED("@" #name)