configure -optimized-qmake makes qmake unusable on Snow Leopard

On a brand-new Mac OS X 10.6 (Snow Leopard) machine, calling configure with -optimized-qmake results in the following error when executing the "make" step:

make: *** No rule to make target `FORCE', needed by `sub-tools-bootstrap-make_default-ordered'. Stop.

This is the first and only line of output issued by make.

The full configure line used is:

configure -qt-libpng -qt-libjpeg -plugin-sql-sqlite -plugin-sql-odbc -plugin-sql-psql -framework -confirm-license -no-rpath -I/usr/local/pgsql/include -L/usr/local/pgsql/lib -optimized-qmake -cocoa -arch x86 -arch x86_64 -sdk /Developer/SDKs/MacOSX10.5.sdk

If -optimized-qmake is removed fromt his line, the build is successful.

Also, if the original configure command is used on Mac OS X 10.5 (Leopard), the build is successful.