Comment 24 for bug 604874

In tracemonkey tip, we have this in jsstr.cpp:

  JSString JSString::unitStringTable[]
  #ifdef __GNUC__
  __attribute__ ((aligned (8)))
  #endif
  = {
      U(0x00), U(0x01), U(0x02), U(0x03), U(0x04), U(0x05), U(0x06), U(0x07),
      U(0x08), U(0x09), U(0x0a), U(0x0b), U(0x0c), U(0x0d), U(0x0e), U(0x0f),
      ...

Is that __attribute__ in your jsstr.cpp?

If not, try updating to tip and building that.