Get MDX tests working on Windows

Author: polytypic

README.md

@@ -752,12 +752,17 @@ Eio.Io Net Connection_failure Refused Unix_error (Connection refused, "connect",
 ```
 
 If we ran this using another backend, the `Unix_error` part might change.
-To avoid this problem, you can use `Eio.Exn.Backend.show` to hide the backend-specific part of errors:
+To avoid this problem, you can use `Eio.Exn.Backend.show`
 
 ```ocaml
 # Eio.Exn.Backend.show := false;;
 - : unit = ()
+```
+
+to hide the backend-specific part of errors:
 
+<!-- $MDX skip -->
+```ocaml
 # Eio_main.run @@ fun env ->
   let net = Eio.Stdenv.net env in
   Switch.run @@ fun sw ->
@@ -882,6 +887,7 @@ perhaps with `open_dir` to constrain all access to be within that directory.
 
 Spawning a child process can be done using the [Eio.Process][] module:
 
+<!-- $MDX non-deterministic=command -->
 ```ocaml
 # Eio_main.run @@ fun env ->
   let proc_mgr = Eio.Stdenv.process_mgr env in
@@ -893,6 +899,7 @@ hello
 There are various optional arguments for setting the process's current directory or connecting up the standard streams.
 For example, we can use `tr` to convert some text to upper-case:
 
+<!-- $MDX non-deterministic=command -->
 ```ocaml
 # Eio_main.run @@ fun env ->
   let proc_mgr = Eio.Stdenv.process_mgr env in
@@ -905,6 +912,7 @@ ONE TWO THREE
 If you want to capture the output of a process, you can provide a suitable `Eio.Flow.sink` as the `stdout` argument,
 or use the `parse_out` convenience wrapper:
 
+<!-- $MDX non-deterministic=command -->
 ```ocaml
 # Eio_main.run @@ fun env ->
   let proc_mgr = Eio.Stdenv.process_mgr env in
@@ -914,6 +922,7 @@ or use the `parse_out` convenience wrapper:
 
 All process functions either return the exit status or check that it was zero (success):
 
+<!-- $MDX non-deterministic=command -->
 ```ocaml
 # Eio_main.run @@ fun env ->
   let proc_mgr = Eio.Stdenv.process_mgr env in

dune

@@ -2,5 +2,4 @@
   (package eio_main)
   (deps (package eio_main) (package kcas) (env_var "EIO_BACKEND"))
   (preludes doc/prelude.ml)
-  (enabled_if (<> %{os_type} "Win32"))
   (files README.md))