Errors compiling demand-accept.c

There is a problem compiling demand-accept.c

demand-accept.c:58:2: warning: incompatible implicit declaration of built-in function ‘bzero’ bzero(&act, sizeof(act)); ^ demand-accept.c:35:35: warning: incompatible implicit declaration of built-in function ‘abort’ #define PANIC(msg) { perror(msg); abort(); } ^ demand-accept.c:61:3: note: in expansion of macro ‘PANIC’ PANIC("SigAction"); ^ demand-accept.c:35:35: warning: incompatible implicit declaration of built-in function ‘abort’ #define PANIC(msg) { perror(msg); abort(); }