I have a command-line executable in Xcode.
I am using Xcode 5.1. In the \"Scheme Editor\" for the project under \"Options\" there is an option for \"Working Directory\".
In Xcode preferences you can change the location of the compiled binaries to be relative to your project, or at any absolute path you like. Go to Preferences->Locations and then click on the Advanced... button below the Derived Data text field.
In the sheet that pops up set the Build Location to Custom, and then select the desired option in the nearby dropdown, and enter whatever paths you like in the Products field.

You can use Xcode build setting variables such as PROJECT_DIR, e.g. setting your working directory to $PROJECT_DIR/.. will make it equal to the parent directory of your project directory.