message: update generic preamble
diff: # define JEMALLOC_N(n) jet_##n
  # include "jemalloc/internal/public_namespace.h"
  # define JEMALLOC_NO_RENAME
  -# include "../jemalloc.h"
  +# include "jemalloc/jemalloc.h"
  # undef JEMALLOC_NO_RENAME
  #else
  # define JEMALLOC_N(n) je_##n
  -# include "../jemalloc.h"
  +# include "jemalloc/jemalloc.h"
  #endif
  #if defined(JEMALLOC_OSATOMIC)
  