ripper.y: get rid of compile error

yystpcpy is always used by yysyntax_error in bison 2.3, but may
not used by other than yytnamerr in newer bison.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66905 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

parse.y

@@ -611,9 +611,6 @@ rb_strterm_mark(VALUE obj)
 
 #define yytnamerr(yyres, yystr) (YYSIZE_T)rb_yytnamerr(yyres, yystr)
 size_t rb_yytnamerr(char *yyres, const char *yystr);
-#ifdef RIPPER
-#define yystpcpy Not used
-#endif
 
 #define TOKEN2ID(tok) ( \
     tTOKEN_LOCAL_BEGIN<(tok)&&(tok)<tTOKEN_LOCAL_END ? TOKEN2LOCALID(tok) : \
@@ -11650,6 +11647,8 @@ Init_ripper(void)
     id_warning = rb_intern_const("warning");
     id_gets = rb_intern_const("gets");
 
+    (void)yystpcpy; /* may not used in newer bison */
+
     InitVM(ripper);
 }