Support exit status for exit/wait

One test case for returning a exit status
Passes usertests, but haven't used it to simplify tests

1 files changed, 1 insertions, 1 deletions

diff --git a/user/echo.c b/user/echo.c
index d0ac6ab..3f19cd7 100644
--- a/user/echo.c
+++ b/user/echo.c
@@ -15,5 +15,5 @@ main(int argc, char *argv[])
       write(1, "\n", 1);
     }
   }
-  exit();
+  exit(0);
 }