fix(haiku): execve not allowed if other pthreads have already been cr…

…eated

Co-authored-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>
Signed-off-by: Anarchos <sylvain_kerjean@hotmail.com>
Signed-off-by: Sylvain78 <sylvain_kerjean@hotmail.com>

otherlibs/stdune/src/proc.ml

@@ -11,7 +11,7 @@ let restore_cwd_and_execve prog argv ~env =
   (* run at_exit before changing the working directory *)
   Stdlib.do_at_exit ();
   Sys.chdir (Path.External.to_string Path.External.initial_cwd);
-  if Sys.win32
+  if Sys.win32 || Platform.OS.value = Platform.OS.Haiku
   then (
     let pid = Unix.create_process_env prog argv env Unix.stdin Unix.stdout Unix.stderr in
     match snd (Unix.waitpid [] pid) with