Adding a Conditional Build Setting
Click Build Settings at the top of the project editor.
Select the build setting to which you want to add a conditional definition.
From the Add Build Setting menu in the lower-right corner, choose Add Conditional Setting.
Choose a condition from the pop-up menu in the left column.
Choose a value from the pop-up menu in the right column.
Customize the build process by choosing conditions under which particular build setting specifications apply. Conditional build setting definitions allow you to add build setting values that apply only when one or more conditions are met. You can add a conditional build setting at the project level and target level.
The video illustrates building a 32-bit universal binary when the architecture is OS X v. 10.5.
© 2012 Apple Inc. All Rights Reserved. (Last updated: 2012-01-09)