"GarageBand Software. You may use the Apple and third party audio loop content (Audio Content), contained in or otherwise included with the Apple Software, on a royalty-free basis, to create your own original music compositions or audio projects. You may broadcast and/or distribute your own music compositions or audio projects that were created using the Audio Content, however, individual audio loops may not be commercially or otherwise distributed on a standalone basis, nor may they be repackaged in whole or in part as audio samples, sound effects or music beds."
So I think I'm good then, since I'm not redistributing the loops/jingles as another jingle for someone else to use in their work. It's just going to be played at the startup screen for my friend's flash game.