Need terminal emulator conversion to GCD/threads

I am needing some work on converting a iOS terminal emulator app to use threads or Grand Central Dispatch instead of the fork/execv in the current version. If you can do this within the budget I would love to hear from you. I want to sell this app in the appstore so I cant use fork/execv/forkpty. The current version is opensource, but does not compile on the latest version of xcode, and is using the forbidden forking. We can also work out arrangements such that you will receive $0.50 per copy sold in the appstore above the amount agreed upon here at freelancer.