Fix and cleanup ceghi_add_sample macro.
Fix and cleanup ceghi_add_sample macro.

Now does the right thing on OS X, should still work everywhere else too.

ruleless/CEGUI,ruleless/CEGUI,OpenTechEngine/CEGUI,OpenTechEngine/CEGUI,ruleless/CEGUI,OpenTechEngine/CEGUI,ruleless/CEGUI,OpenTechEngine/CEGUI