I used the latest Xcode and the 10.7 SDK. Configures, and compiles
(for a while? all that is expected?), but then fails with cp:
.../workdir/unxmacxi.pro/UnpackedTarball/python3/python is a directory
(not copied). That is from ExternalPackage_python3.mk.

No idea how well, if at all, it configures and builds using the Xcode
2 or 3 compiler and 10.4 or 10.5 SDK.

Change-Id: I3ae838263a4db1b67e7c835e567540fac60b98bf