Running ld in verbose mode

This really helped to find out in more details when there is an ld issues

ld -lfftw --verbose

attempt to open /usr/x86_64-redhat-linux/lib64/libfftw.so failed
attempt to open /usr/x86_64-redhat-linux/lib64/libfftw.a failed
attempt to open /usr/local/lib64/libfftw.so failed
attempt to open /usr/local/lib64/libfftw.a failed
attempt to open /lib64/libfftw.so failed
attempt to open /lib64/libfftw.a failed
attempt to open /usr/lib64/libfftw.so failed
attempt to open /usr/lib64/libfftw.a failed
attempt to open /usr/x86_64-redhat-linux/lib/libfftw.so failed
attempt to open /usr/x86_64-redhat-linux/lib/libfftw.a failed
attempt to open /usr/lib64/libfftw.so failed
attempt to open /usr/lib64/libfftw.a failed
attempt to open /usr/local/lib/libfftw.so failed
attempt to open /usr/local/lib/libfftw.a failed
attempt to open /lib/libfftw.so failed
attempt to open /lib/libfftw.a failed
attempt to open /usr/lib/libfftw.so failed
attempt to open /usr/lib/libfftw.a failed
ld: cannot find -lfftw