Beta version 3.6.0 does fix the problem referenced in the linked post.
To define the preprocessor names, go to the slickedit preferences / application languages / c++ and go to the C++ Preprocessor and define or undef the variable you want.
An important caveat is that these preferences are a slickedit setting, so these settings apply to all projects and workspaces. If you cross compile with different definitions, you may need to undef some variables and redefine others.
<hint>I would love to see this migrated to a project level so I could have multiple projects in a workspace with different preprocessor definitions.</hint>