prefix=/opt/Tools/fftw-3.3.8/install
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: FFTW
Description: fast Fourier transform library
Version: 3.3.8
Libs: -L${libdir} -lfftw3 
Libs.private: -lm
Cflags: -I${includedir}