Emit deprecatation warnings for rb_iterate()

* It is obsolete since 1.9, see
  https://github.com/ruby/ruby/blob/master/doc/extension.rdoc#label-Control+Structure
  and [Misc #18025]

include/ruby/internal/iterator.h

@@ -45,6 +45,7 @@ int rb_keyword_given_p(void);
 int rb_block_given_p(void);
 void rb_need_block(void);
 VALUE rb_iterate(VALUE(*)(VALUE),VALUE,rb_block_call_func_t,VALUE);
+DEPRECATED_BY(rb_block_call since 1.9, VALUE rb_iterate(VALUE(*)(VALUE),VALUE,rb_block_call_func_t,VALUE));
 VALUE rb_block_call(VALUE,ID,int,const VALUE*,rb_block_call_func_t,VALUE);
 VALUE rb_block_call_kw(VALUE,ID,int,const VALUE*,rb_block_call_func_t,VALUE,int);
 VALUE rb_rescue(VALUE(*)(VALUE),VALUE,VALUE(*)(VALUE,VALUE),VALUE);

proc.c

@@ -3152,18 +3152,6 @@ method_inspect(VALUE method)
     return str;
 }
 
-static VALUE
-mproc(VALUE method)
-{
-    return rb_funcallv(rb_mRubyVMFrozenCore, idProc, 0, 0);
-}
-
-static VALUE
-mlambda(VALUE method)
-{
-    return rb_funcallv(rb_mRubyVMFrozenCore, idLambda, 0, 0);
-}
-
 static VALUE
 bmcall(RB_BLOCK_CALL_FUNC_ARGLIST(args, method))
 {
@@ -3175,7 +3163,7 @@ rb_proc_new(
     rb_block_call_func_t func,
     VALUE val)
 {
-    VALUE procval = rb_iterate(mproc, 0, func, val);
+    VALUE procval = rb_block_call(rb_mRubyVMFrozenCore, idProc, 0, 0, func, val);
     return procval;
 }
 
@@ -3201,7 +3189,7 @@ method_to_proc(VALUE method)
      *   end
      * end
      */
-    procval = rb_iterate(mlambda, 0, bmcall, method);
+    procval = rb_block_call(rb_mRubyVMFrozenCore, idLambda, 0, 0, bmcall, method);
     GetProcPtr(procval, proc);
     proc->is_from_method = 1;
     return procval;

vm_eval.c

@@ -1557,15 +1557,22 @@ rb_iterate0(VALUE (* it_proc) (VALUE), VALUE data1,
     return retval;
 }
 
-VALUE
-rb_iterate(VALUE (* it_proc)(VALUE), VALUE data1,
-           rb_block_call_func_t bl_proc, VALUE data2)
+static VALUE
+rb_iterate_internal(VALUE (* it_proc)(VALUE), VALUE data1,
+                    rb_block_call_func_t bl_proc, VALUE data2)
 {
     return rb_iterate0(it_proc, data1,
 		       bl_proc ? rb_vm_ifunc_proc_new(bl_proc, (void *)data2) : 0,
 		       GET_EC());
 }
 
+VALUE
+rb_iterate(VALUE (* it_proc)(VALUE), VALUE data1,
+           rb_block_call_func_t bl_proc, VALUE data2)
+{
+    return rb_iterate_internal(it_proc, data1, bl_proc, data2);
+}
+
 struct iter_method_arg {
     VALUE obj;
     ID mid;
@@ -1603,7 +1610,7 @@ rb_block_call_kw(VALUE obj, ID mid, int argc, const VALUE * argv,
     arg.argc = argc;
     arg.argv = argv;
     arg.kw_splat = kw_splat;
-    return rb_iterate(iterate_method, (VALUE)&arg, bl_proc, data2);
+    return rb_iterate_internal(iterate_method, (VALUE)&arg, bl_proc, data2);
 }
 
 VALUE
@@ -1644,7 +1651,7 @@ rb_check_block_call(VALUE obj, ID mid, int argc, const VALUE *argv,
     arg.argc = argc;
     arg.argv = argv;
     arg.kw_splat = 0;
-    return rb_iterate(iterate_check_method, (VALUE)&arg, bl_proc, data2);
+    return rb_iterate_internal(iterate_check_method, (VALUE)&arg, bl_proc, data2);
 }
 
 VALUE