Replace GTimeVal with GDateTime
Related: thunar#125 (xfce/thunar#125 (closed))
GTimeVal is deprecated due to Y2038 problem, and replaced with GDateTime.
Note: GTimeVal is introduced in Glib 2.26 and this plugin depends on GTK >=3.20, which depends on Glib >=2.45.8
Edited by Yongha Hwang