Kernel/LibC: Implement alarm() and setitimer()

This makes vim able to start!

userspace/libraries/LibC/sys/time.cpp

@@ -1,5 +1,7 @@
+#include <sys/syscall.h>
 #include <sys/time.h>
 #include <time.h>
+#include <unistd.h>
 
 int gettimeofday(struct timeval* __restrict tp, void* __restrict tzp)
 {
@@ -13,3 +15,8 @@ int gettimeofday(struct timeval* __restrict tp, void* __restrict tzp)
 	tp->tv_usec = ts.tv_nsec / 1000;
 	return 0;
 }
+
+int setitimer(int which, const struct itimerval* __restrict value, struct itimerval* __restrict ovalue)
+{
+	return syscall(SYS_SETITIMER, which, value, ovalue);
+}