Its not clear from the readme in the src/adium directory where to set the NSS_SRCPATH and ADIUM_SRCPATH. When trying to compile in Xcode the Adium Libraries/Framework cannot be found for the include statements.
How should this be setup to compile the sipe adium plugin?
Those are set in the xcode project. Make sure the project is selected (not the one of the targets) and then click "Add Build Setting" and "Add User-Defined Setting".
That will work, but I wrote the README with the intent that these variables would be configured in the xCode "Source Tree" preferences section. That way it doesn't pollute the project file with a hard coded directory.