cmake find_package(FFTW3f) examples

gnuradio/gnuradio gr-fft/CMakeLists.txt :13 

find_package(FFTW3f)

InsightSoftwareConsortium/ITK CMake/itkExternal_FFTW.cmake :100 

# Can not find package, it does not yet exist find_package(FFTW3f CONFIG REQUIRED)