#13 make-icon sometimes crashes scwm

[Scott Lenser]

make-icon sometimes crashes scwm.

apply the style (title-style #:pixmap "a036") to
trigger problem.

(define w (get-window))
(define d (make-decor))
(set-window-decor! w d)
(with-decor d (title-style #:pixmap "a036" #:relief
'flat #:active-down (list #:v-gradient (list 50
'("black" 100) "red") #:relief 'raised) #:inactive
(list #:h-gradient (list 100 '("black" 100) "red")
#:relief 'flat)))

is reproduction recipe.