Adding the new C files too.

sync.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <unistd.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: sync\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	if(argc != 1)
+		usage();
+	sync();
+
+	return 0;
+}
+