Lazarus treats include files (*.inc) as a part of a project. That means you should not bother where you store include files in a project – just
Not so in Delphi (Delphi XE to be exact). You can add *.inc file to a Delphi project, but it does not matter for Delphi, you still need to write paths to include files like that
and sure the paths are different for units in different project folders.