NSSliderCell bug on solaris9 sparc

[UBoss UBoss]

Hi 
On sparc with solaris 9 gnustep10.2 (make-1.11.2, base-1.11.2, gui-0.10.2, back-0.10.2) 
NSSliderCell crashs on setKnobThickness it takes size from nil image and then setting new size to nil image
fast repair is to replace in gui/sources/NSSliderCell.m 
 -(void)setKnobThickness: (float)thickness

NSSize size = [image size];
with 
NSSize size = image ? [image size] : NSZeroSize;

by for now uboss