-extern NCURSES_EXPORT(int) sigaction (int sig, sigaction_t * sigact, sigaction_t * osigact);
-extern NCURSES_EXPORT(int) sigprocmask (int how, sigset_t *mask, sigset_t *omask);
-extern NCURSES_EXPORT(int) sigemptyset (sigset_t *mask);
-extern NCURSES_EXPORT(int) sigsuspend (sigset_t *mask);
-extern NCURSES_EXPORT(int) sigdelset (sigset_t *mask, int sig);
-extern NCURSES_EXPORT(int) sigaddset (sigset_t *mask, int sig);