Q:

Add header to every file in project setting (gcc -include)

I have a project which use gcc -include file.h
As gcc documentation say, this ensures that file.h is included in every file which is compiled this way (meaning like there was #include "file.h" in every other files). 
Now I have imported this project into eclipse and I set up the include path where that file is but can't figure out how to do something like gcc -include in eclipse project setting.  The result of this is that in editor I have a LOT of "Symbol xy could not be resolved" but the project compiles just fine. 
Thanks for any help. 

A:

You can change the CDT GCC Built-in Compiler Settings on a project-by-project basis. 

Go to Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros etc.  
Select the Providers tab. 
Select CDT GCC Built-in Compiler Settings
Unselect Use global provider shared between projects
Add the required GCC flags to the Command to get compiler specs: input box

(see highlighted text in image below)

You probably want to click Store entries in project settings folder

