CVS renato: fix compilation warnings

[FVWM CVS]

CVSROOT:        /home/cvs/fvwm
Module name:    fvwm
Changes by:     renato  07/08/29 06:39:20

Modified files:
        modules        : ChangeLog 
        modules/FvwmButtons: button.c 
        modules/FvwmTaskBar: Start.c 

Log message:
fix compilation warnings