Without it the install process works fine but then running glances you get the error: $ glances Curses module not found. Glances cannot start.
+*glances-1.6.1 (20 May 2013) + + 20 May 2013; Kacper Kowalik <xarthisius@gentoo.org> +glances-1.6.1.ebuild, + -glances-1.6.ebuild: + Version bump, depend properly on python[ncurses] wrt bug 460068 by Albert W. + Hopkins <marduk@python.net>, check for required kernel options. Drop old +