Use --combined thread
- FFTW now relies on --combine threads to be compatible with FFTW.jl
- nimfftw3 can now compile and install FFTW3 for source. This is untested for windows at the moment.
- use -d:localFftw3 to use the fftw3 installed y Nimble. Otherwise, use your system install through LD_LIBRARY_PATH