check necessary functions.

Author: nobu

ext/ruby_debug/extconf.rb

@@ -6,14 +6,14 @@
     have_struct_member("rb_method_entry_t", "called_id", "method.h") or
     have_struct_member("rb_control_frame_t", "method_id", "method.h")
   end and
+  begin
+    have_func("rb_method_entry", "method.h") or
+    have_func("rb_method_node", "node.h")
+  end and
   have_header("vm_core.h") and have_header("iseq.h") and have_header("insns.inc") and
   have_header("insns_info.inc") and have_header("eval_intern.h")
 }
 
-if RUBY_VERSION == '1.9.1'
-  $CFLAGS << ' -DRUBY_VERSION_1_9_1'
-end
-
 if RUBY_REVISION >= 26959 # rb_iseq_compile_with_option was added an argument filepath  
   $CFLAGS << ' -DRB_ISEQ_COMPILE_6ARGS'
 end

ext/ruby_debug/ruby_debug.c

@@ -137,7 +137,7 @@ real_class(VALUE klass)
 inline static void *
 ruby_method_ptr(VALUE class, ID meth_id)
 {
-#ifdef RUBY_VERSION_1_9_1
+#ifndef HAVE_RB_METHOD_ENTRY
     NODE *body, *method;
     st_lookup(RCLASS_M_TBL(class), meth_id, (st_data_t *)&body);
     method = (NODE *)body->u2.value;
@@ -726,7 +726,7 @@ debug_event_hook(rb_event_flag_t event, VALUE data, VALUE self, ID mid, VALUE kl
     char *file = (char*)rb_sourcefile();
     int line = rb_sourceline();
     int moved = 0;
-#ifdef RUBY_VERSION_1_9_1
+#ifndef HAVE_RB_METHOD_ENTRY
     NODE *node = NULL;
 #else
     rb_method_entry_t *me = NULL;
@@ -748,7 +748,7 @@ debug_event_hook(rb_event_flag_t event, VALUE data, VALUE self, ID mid, VALUE kl
 
     if (mid == ID_ALLOCATOR) return;
 
-#ifdef RUBY_VERSION_1_9_1
+#ifndef HAVE_RB_METHOD_ENTRY
     node = rb_method_node(klass, mid);
 #else
     me = rb_method_entry(klass, mid);
@@ -964,7 +964,7 @@ debug_event_hook(rb_event_flag_t event, VALUE data, VALUE self, ID mid, VALUE kl
     case RUBY_EVENT_C_RETURN:
     {
         /* note if a block is given we fall through! */
-#ifdef RUBY_VERSION_1_9_1
+#ifndef HAVE_RB_METHOD_ENTRY
         if(!node || !c_call_new_frame_p(klass, mid))
 #else
         if(!me || !c_call_new_frame_p(klass, mid))