optfeature: stub out the eclass

This eclass just generates elog spam that we don't need or care
about, so stub out its functionality.

BUG=None
TEST=CQ passes

Change-Id: I2f89b88d9b8161f169ea71ab4a307b25349b596d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/eclass-overlay/+/2935926
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/eclass/optfeature.eclass b/eclass/optfeature.eclass
new file mode 100644
index 0000000..f6a2d6e
--- /dev/null
+++ b/eclass/optfeature.eclass
@@ -0,0 +1,20 @@
+# Copyright 1999-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: optfeature.eclass
+# @MAINTAINER:
+# base-system@gentoo.org
+# @BLURB: Advertise optional functionality that might be useful to users
+
+case ${EAPI:-0} in
+	[0-7]) ;;
+	*)     die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}" ;;
+esac
+
+if [[ -z ${_OPTFEATURE_ECLASS} ]]; then
+_OPTFEATURE_ECLASS=1
+
+# Stub this out for CrOS as it's just annoying log spam for us.
+optfeature() { :; }
+
+fi