libqtprofilesetup: Set up ios-specific flags at setup time.

This enables us to get rid of qtfunctions.js.

Change-Id: I4cf593742f7afcfb9caa8e2984b11b80d4fb6265
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>