(Eclipse) How to add directories to GCC include path

This is exactly the same problem I am having. I added my include paths under C/C++ General -> Paths and Symbols. This did not let the compiler find my include paths other than the default ones and I could see the gcc lines did not mention my paths. Project Explorer DID display the paths under Includes. I then added the paths under Nios II Application Properties. I selected Convert Relative Path and hit Apply and Close. Nothing changed in the project explorer, i.e. the new paths weren't listed. I opened the project properties again and went to the Nios II Application Properties section, and the relative paths were gone, as if I had never added them. I added them as absolute paths and they appeared in the project explorer AND under the C/C++ General -> Paths and Symbols section. It seems that C/C++ General -> Paths and Symbols is only for displaying the defaults and what is added, not for actually adding anything despite the fact the interface makes you think you can.

There is something wrong here. The C/C++ General -> Paths and Symbols section and the Nios II Application Properties seem to do the same thing, even though only the latter really works. Also, the relative paths do not appear to work or even be saved.