Add mikecat's argp test

usertests.c

@@ -1724,6 +1724,19 @@ uio()
   printf(1, "uio test done\n");
 }
 
+void argptest()
+{
+  int fd;
+  fd = open("init", O_RDONLY);
+  if (fd < 0) {
+    printf(2, "open failed\n");
+    exit();
+  }
+  read(fd, sbrk(0) - 1, -1);
+  close(fd);
+  printf(1, "arg test passed\n");
+}
+
 unsigned long randstate = 1;
 unsigned int
 rand()
@@ -1743,6 +1756,7 @@ main(int argc, char *argv[])
   }
   close(open("usertests.ran", O_CREATE));
 
+  argptest();
   createdelete();
   linkunlink();
   concreate();