/usr/share/common-lisp/systems/cl-fftw3.asd is in cl-fftw3 1.0-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/common-lisp/systems/../source/cl-fftw3/cl-fftw3.asd
/usr/share/common-lisp/systems/../source/cl-fftw3/cl-fftw3.asd