How to change Xcode build setup without modifying project files?

Question

I would like to know if it is possible to change compile settings without modifying the xcode projects.

Example, adding -Wno-unused-parameter to CFLAG

Answer 1

Put the compiler settings you want to change in a configuration settings file. You can create a new one by choosing File > New > New File. The configuration settings file is in the Other group under both iOS and Mac OS X.

To tell an Xcode project to use the configuration settings file, select the project file from the project navigator to open the project editor. Select the project from the left side of the editor. Click the Info button at the top of the editor. You should see a list of build configurations in the editor. Click the disclosure triangle next to a build configuration to have it use a configuration settings file.