+/*
+ * x86/darwin (as of MacOS X 10.4.5) doesn't reliably file signal
+ * handlers (SIGTRAP or Mach exception handlers) for 0xCC, wo we have
+ * to use ud2 instead. ud2 is an undefined opcode, #x0b0f, or
+ * 0F 0B in low-endian notation, that causes SIGILL to fire. We check
+ * for this instruction in the SIGILL handler and if we see it, we
+ * advance the EIP by two bytes to skip over ud2 instruction and
+ * call sigtrap_handler. */