According to one of your screenshots, if you select "proj1" in the "Project build options", you can select the project-global build options. These apply usually to all build targets. In your case "default" is the build target. If you select it you can set the target build options. You can also choose how the target options are combined with the project options: They can be appended, prepended, they can replace the project options or they can be ignored (project options only).