-# ifdef HAVE_GC_GC_H
-# include <gc/gc.h>
-# include <gc/gc_typed.h>
-# include <gc/gc_mark.h>
-# include <gc/gc_gcj.h>
-# elif defined(HAVE_GC_H) || defined(USE_INCLUDED_LIBGC)
-# include <gc.h>
-# include <gc_typed.h>
-# include <gc_mark.h>
-# include <gc_gcj.h>
-# else
-# error have boehm GC without headers, you probably need to install them by hand
-# endif