TBB "Directory is not set"

<code>
CMake Error at adm/cmake/tbb.cmake:8 (message):
Directory is not set.
Call Stack (most recent call first):
CMakeLists.txt:34 (include)
CMakeLists.txt:725 (OCCT_INCLUDE_CMAKE_FILE)

-- Configuring incomplete, errors occurred!
</code>

I've successfully built opencascade-7.6.3 against https://archlinux.org/packages/extra/x86_64/tbb/ but against git master (7.7.0) the build now fails.