Install out of tree configs for Chrome OS builds of U-Boot.

chromeos-base/u-boot-config/u-boot-config-9999.ebuild

+# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=2
+
+DESCRIPTION="ChromeOS specific U-Boot configurations"
+HOMEPAGE="http://chromium.org"
+LICENSE="BSD"
+SLOT="0"
+KEYWORDS="~arm"
+IUSE=""
+
+RDEPEND=""
+DEPEND=""
+
+# This must be inherited *after* EGIT/CROS_WORKON variables defined
+inherit cros-workon
+
+src_install() {
+        local arch=$(echo ${CHROMEOS_U_BOOT_CONFIG} | cut -d_ -f2)
+        local board=${arch}/$(echo ${CHROMEOS_U_BOOT_CONFIG} | cut -d_ -f3)
+
+        for directory in . ${arch} ${arch}/parts ${board} ${board}/parts; do
+                dodir /u-boot/configs/chromeos/${directory}
+                insinto /u-boot/configs/chromeos/${directory}
+
+                doins ${directory}/* || die
+        done
+}