Since Xcode 3.1.4 is the last version which runs under 10.5, native builds aren't possible on 10.5 without Xcode 3.1 support. There are at least three changes needed to fully support Xcode 3.1, only two of which are included here: 1) Adding 3.1 entries to the Xcode-version-specific areas. 2) Falling back to kextload when kextutil is not present. In 10.5/3.1, the developer-only kextload options had not yet been split off into kextutil, making kextload a drop-in replacement. 3) Providing a substitute for pkgbuild, which is missing in the 10.5/3.1 environment. There does not appear to be a trivial solution to this one. Without a fix for #3, the "dist" and "smalldist" targets still don't work in 10.5/3.1, but the other targets do, including the "homebrew" target used by MacPorts.