I have created an \'External Build Project\' in Xcode 4 using a makefile. The project builds perfectly, except the only way I know how to get it to run is in Terminal.
Yes, you can!
Product -> Edit scheme
Select "Run" from the left panel, select "Info" from top and specify "Executable" drop list
Select next pane "Arguments" and add "Arguments Passed On Launch" (to "Executable" you select before)