Includes stuff in header for rsh_server.c

Assignment-06/starter/rsh_server.c

@@ -8,6 +8,7 @@
 #include <unistd.h>
 #include <sys/un.h>
 #include <fcntl.h>
+#include <errno.h>
 
 //INCLUDES for extra credit
 //#include <signal.h>