what is the best practice to reference 3rd party C++ components (e.g. includes, libraries) using relative paths in Eclipse-CDT?
I solved this problem using the Preferences->General->Workspace->Linked Resources option.
Basically you define a variable pointing to your workspace folder.
Then add to your project the third-party folder using Add folder->Advanced->Link to folder in the filesystem, and use the Variables... button to use the previously created variable to point to the third-party folder (using the Extend button).
Then you just need to add the folder to your include and library paths in the project settings.
Easy as cake... :S