ksynaptics is not working and the source packages are not gcc4 patched. 
 
I had the problem with Fedora Core 4 some weeks ago, and contacted the 
maintainer, Stefan Kombrink. 
 
He aa 
nswered (translated into english): 
 
> Okay, ich had a second look into the sources: 
> 
> in touchpad.h: 
> ============== 
> Delete the line 
> static const double coastingSpeedThreshold = 38 
>  
> 
> in touchpad.cpp: 
> =============== 
> 
> void TouchPad::setCoastingEnabled( bool enable ) 
> { 
>   if ( !isValid() ) 
>     return; 
> 
>   if ( enable ) 
>     SYNSHM->coasting_speed = coastingSpeedThreshold; // set to reasonable 
> speed 
>   else 
>     SYNSHM->coasting_speed = 0.0; // disable it completely 
> } 
> 
> exchange with 
> 
> void TouchPad::setCoastingEnabled( bool enable ) 
> { 
>   if ( !isValid() ) 
>     return; 
> 
>   if ( enable ) 
>     SYNSHM->coasting_speed = 38; 
>   else 
>     SYNSHM->coasting_speed = 0.0; // disable it completely 
> } 
 
This solved the problem with Fedora Core 4. 
 
You can contact the author by yourself, he is very friendly, but very busy 
abousynaptics at the moment because they try to integrate it into KDE 3.5. 
 
Roland