signal: add sigisemptyset, sigandset, sigorset api
refs:https://man7.org/linux/man-pages/man3/sigorset.3.html
# define SIG_HOLD ((_sa_handler_t)1) /* Used only with sigset() */
#endif
+#define sigisemptyset(set) (!*(set))
+#define sigorset(dest, left, right) (!(*(dest) = *(left) | *(right)))
+#define sigandset(dest, left, right) (!(*(dest) = *(left) & *(right)))
+
/********************************************************************************
* Public Types
********************************************************************************/
