prefix symbols exported for mjit

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64031 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

vm.c

@@ -12,6 +12,11 @@
 #include "ruby/vm.h"
 #include "ruby/st.h"
 
+#define vm_call0 rb_vm_call0
+#define vm_exec rb_vm_exec
+#define vm_invoke_bmethod rb_vm_invoke_bmethod
+#define vm_search_method_slowpath rb_vm_search_method_slowpath
+
 #include "gc.h"
 #include "vm_core.h"
 #include "vm_debug.h"