diff --git a/binding-mri/binding-mri.cpp b/binding-mri/binding-mri.cpp
index b0e4d11..01599c8 100644
--- a/binding-mri/binding-mri.cpp
+++ b/binding-mri/binding-mri.cpp
@@ -126,7 +126,7 @@ static void mriBindingInit()
 	_rb_define_module_function(rb_mKernel, "caller", _kernelCaller);
 #endif
 
-	rb_define_global_const("MKXP", Qtrue);
+	rb_gv_set("MKXP", Qtrue);
 }
 
 static void