only set LIBFFT when Intel MKL FFTW interface libraries are present
take into account that FFT_LIB_DIR is a list of dirs
fix typo
fix another typo
check for Intel MKL FFTW interface libraries full path
make existing code robust against empty list of libs
use get_software_root to get installation dir of IMKL
use env var name prefix constants from modules.py in easyblock.py
Merge branch 'develop' into optional_intel_fftw_wrappers
fix typo
Merge branch 'develop' into optional_intel_fftw_wrappers
add log.deprecated for supporting SOFT* env vars
use all from vsc.utils.missing, fix bug in any (return\!)
don't allow FFTW interfaces to missing in an ictce toolchain
Merge pull request #518 from boegel/optional_intel_fftw_wrappers

only define LIBFFT for Intel MKL if FFTW interface is available