cow lab initialized

kernel/syscall.c

@@ -101,8 +101,6 @@ extern uint64 sys_unlink(void);
 extern uint64 sys_link(void);
 extern uint64 sys_mkdir(void);
 extern uint64 sys_close(void);
-extern uint64 sys_sigalarm(void);
-extern uint64 sys_sigreturn(void);
 
 // An array mapping syscall numbers from syscall.h
 // to the function that handles the system call.
@@ -128,8 +126,6 @@ static uint64 (*syscalls[])(void) = {
 [SYS_link]    sys_link,
 [SYS_mkdir]   sys_mkdir,
 [SYS_close]   sys_close,
-[SYS_sigalarm] sys_sigalarm,
-[SYS_sigreturn] sys_sigreturn,
 };
 
 void