As far I know, gcc is the compiler used for all cocoa/c++ apps and stuff. I think only the new Xcode supports the 4.0 version. If you want to use it with a previous Xcode version, you will probably have to use an earlier version of your script or change the command line 19 to suit your needs.
Thanks for the reply, BTW i’m new to the language, could you please tell me what the command line 19 refers to? is it the line number in the script or does it refer to something else? thanks