If you right-click on the project node (any project, not just Delphi Prism) in the solution explorer, and then click the "Properties" button in the context menu, the "Project Settings" tab should appear in the text editor panel, click the build tab, it should be the third tab down on the left side. The first text block that appears on this page should be marked as "Conditional compilation characters." It should already contain the characters: "DEBUG; TRACE". You can add your own characters.
You can also go to the “Project Properties” tab by selecting the project node in the solution explorer, and then clicking on the left button of the toolbar in the solution explorer window.
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