Lowercase [Sys.getcwd ()] under Win32

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

src/stdune/path.ml

@@ -140,7 +140,13 @@ end = struct
     let base, _ = split_extension t in
     to_string base ^ ext |> make
 
-  let cwd () = make (Sys.getcwd ())
+  let cwd () =
+    let s = Sys.getcwd () in
+    make
+      ( if Sys.win32 then
+        String.lowercase s
+      else
+        s )
 
   let initial_cwd = cwd ()