Fix #1234 and extend watch to DELETE event (#1235)

Signed-off-by: Pavel Senchanka <pavel.senchanka@gmail.com>

bin/main.ml

@@ -149,7 +149,7 @@ let watch_command =
     | Some inotifywait ->
       (* On Linux, use inotifywait. *)
       let excludes = String.concat ~sep:"|" excludes in
-      inotifywait, ["-r"; path; "--exclude"; excludes; "-e"; "close_write"; "-q"]
+      inotifywait, ["-r"; path; "--exclude"; excludes; "-e"; "close_write"; "-e"; "delete"; "-q"]
     | None ->
       (* On all other platforms, try to use fswatch. fswatch's event
          filtering is not reliable (at least on Linux), so don't try to

src/dir_contents.ml

@@ -685,7 +685,8 @@ end
 let cache = Hashtbl.create 32
 
 let clear_cache () =
-  Hashtbl.reset cache
+  Hashtbl.reset cache;
+  Hashtbl.reset Dir_status.cache
 
 let () = Hooks.End_of_build.always clear_cache