ruby.h: no warnings of hidden objects

* include/ruby/ruby.h (rb_data_object_alloc_warning): no warnings
  of internal hidden objects which klass == 0.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48692 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/tk/tcltklib.c

@@ -20,7 +20,11 @@
 #endif
 
 #undef RUBY_UNTYPED_DATA_WARNING
+#ifdef HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P
+#define RUBY_UNTYPED_DATA_WARNING 1
+#else
 #define RUBY_UNTYPED_DATA_WARNING 0
+#endif
 
 #ifdef HAVE_RB_THREAD_CHECK_TRAP_PENDING
 static int rb_thread_critical; /* dummy */

include/ruby/ruby.h

@@ -1173,6 +1173,15 @@ rb_data_object_alloc_warning(VALUE klass, void *ptr, RUBY_DATA_FUNC mark, RUBY_D
     return rb_data_object_alloc(klass, ptr, mark, free);
 }
 
+#if defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P)
+#define rb_data_object_alloc_warning(klass, ptr, mark, free) \
+    __extension__( \
+	__builtin_choose_expr( \
+	    __builtin_constant_p(klass) && !(klass), \
+	    rb_data_object_alloc(klass, ptr, mark, free), \
+	    rb_data_object_alloc_warning(klass, ptr, mark, free)))
+#endif
+
 static inline void *
 rb_data_object_get(VALUE obj)
 {