[PyQt] qmake can't find macx-clang?

[David Cortesi]

Installing PyQt5 on Lion (OS X 10.7.5). Qt5 is in /Developer/Qt5 and
/Developer/Qt5/5.2.0/clang_64/bin is on $PATH

> python configure.py --verbose
> Querying qmake about your Qt installation...
> Determining the details of your Qt installation...
> /Developer/Qt5/5.2.0/clang_64/bin/qmake -o qtdetail.mk qtdetail.pro
> Could not find qmake configuration file macx-clang.

That file and others like it are in /Developer/Qt5/5.2.0/clang_64/mkspecs

When I run qmake -query I see it knows:

> QT_INSTALL_PREFIX:/Developer/5.2.0/clang_64
> QMAKE_SPEC:macx-clang
> QMAKE_XSPEC:macx-clang

I also tried setting QTDIR to /Developer/5.2.0/clang_64 with no effect

Suggestions?