gtk2 rbgtkalignment.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtkfilechooserdialog.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtkfilechooser.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtktoggletoolbutton.c: drop GTK_CHECK_VERSION(2,4,0)
gtk2 rbgtkstyle.c: drop GTK_CHECK_VERSION(2,4,0)