CMake bugs with set(var value PARENT_SCOPE)
http://public.kitware.com/Bug/view.php?id=13786 notes that
set(var value PARENT_SCOPE) does not work in 18.104.22.168 or 2.8.11. I've been using lots of 2.8.11 in recent months and not had problems, but we should be alert for this, because any other code we have that tries to be modular with CMake scope may also be broken. Ugh.
cmake .. -DGMX_BUILD_OWN_FFTW=on breaks because such a
set(... PARENT_SCOPE) fails in
src/contrib/fftw/CMakeLists.txt, giving messages like
-- The GROMACS-managed build of FFTW 3 will configure with the following optimizations: --enable-sse2 CMake Error at CMakeLists.txt:915 (MESSAGE): Cannot find FFTW 3 (with correct precision - libfftw3f for single-precision GROMACS or libfftw3 for double-precision GROMACS). Either choose the right precision, choose another FFT(W) library (-DGMX_FFT_LIBRARY), enable the advanced option to let GROMACS build FFTW 3 for you (-DGMX_BUILD_OWN_FFTW=ON) , or use the really slow GROMACS built-in fftpack library (-DGMX_FFT_LIBRARY=fftpack).
because FFTWF_FOUND is not set TRUE. So I think we will need to version this error message by the CMake version, or face a future deluge of posts on gmx-users.