mi: Avoid stack smash when drawing dashed lines
mi: Avoid stack smash when drawing dashed lines

Based off Peter Harris's xserver commit
http://cgit.freedesktop.org/xorg/xserver/commit/mi/miwideline.c?id=20c2a3bcb11b5baf564e2c73a477ba23f5ae2b10

elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,Fantu/spice-common,elmarco/spice-common,elmarco/spice-common,fgouget/spice-common,fgouget/spice-common,SPICE/spice-common,elmarco/spice-common,Fantu/spice-common,fgouget/spice-common,Fantu/spice-common,freedesktop-unofficial-mirror/spice__spice-common,SPICE/spice-common,Fantu/spice-common,SPICE/spice-common,freedesktop-unofficial-mirror/spice__spice-common,freedesktop-unofficial-mirror/spice__spice-common