diff --git a/internal.h b/internal.h
index 8510ed2d1e..2f3124f791 100644
--- a/internal.h
+++ b/internal.h
@@ -95,6 +95,8 @@ extern "C" {
 # define __has_extension __has_feature
 #endif
 
+#ifndef MJIT_HEADER
+
 #ifdef HAVE_SANITIZER_ASAN_INTERFACE_H
 # include <sanitizer/asan_interface.h>
 #endif
@@ -149,6 +151,8 @@ unpoison_object(VALUE obj, bool newobj_p)
     unpoison_memory_region(ptr, SIZEOF_VALUE, newobj_p);
 }
 
+#endif
+
 /* Prevent compiler from reordering access */
 #define ACCESS_ONCE(type,x) (*((volatile type *)&(x)))