gtk2 rbgtkicontheme.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtktooltip.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtktoolbutton.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtktextiter.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtkentrycompletion.c: drop GTK_CHECK_VERSION(2,4,0)