workaround C++ism in ASAN header

See also: https://travis-ci.org/ruby/ruby/jobs/451299690


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

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)))