compatibility

Signed-off-by: Paul-Elliot <[email protected]>

Author: panglesd

src/odoc/occurrences.ml

@@ -1,7 +1,18 @@
 open Or_error
 
+(* Copied from ocaml 5.0 String module *)
+let string_starts_with ~prefix s =
+  let open String in
+  let len_s = length s and len_pre = length prefix in
+  let rec aux i =
+    if i = len_pre then true
+    else if unsafe_get s i <> unsafe_get prefix i then false
+    else aux (i + 1)
+  in
+  len_s >= len_pre && aux 0
+
 let handle_file file ~f =
-  if String.starts_with ~prefix:"src-" (Fpath.filename file) then
+  if string_starts_with ~prefix:"src-" (Fpath.filename file) then
     Odoc_file.load file |> function
     | Error _ as e -> e
     | Ok unit' -> (