It is 3.1 something. I did it almost a year ago, I do not remember the details.
I do not have the installer here to check, but can't you select in Developper Tools what you want (I remember something like that) ? Or may be inspecting the package, you could run just the installer for the compiling and linking tools. I remember it was quite straight forward.
I'll try to update to the latest version, when I am back home in a couple of days and tell you, if it works. Hope you'll find a solution in mean time.
Dell Mini 9, 16 GB SSD, 16 GB SDHC, 2 GB RAM, Wifi, Bluetooth, 1.3 MPx WebCam, OS X 10.5.5 (Vanilla Kernel)