examples: set mode when creating shm object
examples: set mode when creating shm object

$ screencopy
shm_open failed
failed to create buffer

$ posixshmcontrol ls
MODE            OWNER   GROUP   SIZE    PATH
---------       foo     foo     33177600        /wlroots-screencopy

swaywm/wlroots,ascent12/wlroots,SirCmpwn/wlroots,ascent12/wlroots,swaywm/wlroots