Choose one of the "Base SDK" members from the "Overview" popup in the project window.

Been frustrated with getting the proper compiler options turned on and off for iPhone projects because they don’t show up in the build settings?  Me Too.

Many thanks to Rick Maddy for posting the answer to this on iPhoneDevSDK.com so I can finally access the “GCC 4.0 – Code Generation” and “GCC 4.0 – Language” sections correctly.

To see these entries in the settings window,  you must first go to the “Overview” popup menu in the project window and select one of the entries that correspond to the “Base SDK” as specified in the build settings.  If your project’s “Base SDK” (wording used by XCode 3.1.3) is a device, you must select one of the device entries.

Note that for XCode version 3.1.2.  this was referred to as  “(Project Setting)”.  If later or previous versions have different wording, please let me know and I’ll update this.

If any other entry from the popup’s “Active SDK” section is chosen, you will not see these through either method of accessing the build options.   This is typically my problem as the selection spends most of the time on a “Simulator” setting during development.

With another entry, you may see some flags show in the “User Defined” section at the bottom of the build options.  You can still set options with these (as I did before finding out this information.)

The "Base SDK" project setting.

This is just what I needed to address problems like:

“error: ‘for’ loop initial declaration used outside C99 mode”