CVS tadam: Fft: Fix compiler warnings

[cvs]

CVSROOT:        /home/cvs/fvwm
Module name:    fvwm
Changes by:     tadam   14/12/27 18:00:20

Modified files:
        .              : Tag: branch-2_6 ChangeLog 
        libs           : Tag: branch-2_6 Fft.c 

Log message:
Fft:  Fix compiler warnings

Pre-initialise some defined variables to shut GCC up.