libesmtp in Gentoo is built with the configure-command --enable-all which enables a bunch of experimental features. I think some of them should be use-flagged. One where already a semi-default useflag (various other packages use it, but it's not a global use flag) exists is ntlm. It's an ancient microsoft authentication protocol and I think it's rarely needed and whoever needs it probably knows that. (background: the ntlm-code is incompatible with libressl, which should probably be fixed in itself, but the easier way for now is to allow just disabling it, as most people probably won't need it)
+*libesmtp-1.0.6-r1 (19 Jul 2014) + + 19 Jul 2014; Eray Aslan <eras@gentoo.org> +libesmtp-1.0.6-r1.ebuild, + metadata.xml: + Add ntlm USE flag - bug #517142 +
