used for undiagnosed trap exceptions where linux previously set si_code to 0. new in linux commit db78e6a0a6f9f7d7277965600eeb1a5b3a6f55a8
@@ -233,6 +233,7 @@ void (*sigset(int, void (*)(int)))(int);
#define TRAP_TRACE 2
#define TRAP_BRANCH 3
#define TRAP_HWBKPT 4
+#define TRAP_UNK 5
#define POLL_IN 1
#define POLL_OUT 2
#define POLL_MSG 3