Modify to work with cros_workon.

gmerge

 #!/bin/bash
 
 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 set -e
 
 build=1
 
@@ skipping 17 matching lines @@
 
 if [ -z $BOARD_NAME ]
 then
   echo "No board specified in /etc/lsb-release"
   exit 1
 fi
 
 mount -o remount,rw /
 mkdir -p /etc/make.profile
 
+# Delete the local binary package cache.
+sudo rm -rf /usr/portage/packages
+
 if [ $build == 1 ] ; then
   echo "Building $package_name"
   ESCAPED_PACKAGE=$(python -c \
     "import urllib; print urllib.quote('''$package_name''')")
   ESCAPED_BOARD=$(python -c \
   "import urllib; print urllib.quote('''${BOARD_NAME}''')")
 
   wget $DEVKIT_URL/build \
     --post-data="pkg=${ESCAPED_PACKAGE}&board=${ESCAPED_BOARD}"
 fi
@@ skipping 12 matching lines @@
   fi
 fi
 
 echo "Emerging $package_name"
 
 export PORTAGE_BINHOST="${DEVKIT_URL}/static/pkgroot/${BOARD_NAME}/packages"
 export PORTAGE_TMPDIR=/tmp
 
 # Accept keywords only for stable ebuilds by default.
 if [ -z "$ACCEPT_KEYWORDS" ] ; then
-  ACCEPT_KEYWORDS='arm x86'
+  ACCEPT_KEYWORDS='arm x86 ~arm ~x86'
 fi
 export ACCEPT_KEYWORDS
 
 FEATURES="-sandbox" emerge --getbinpkg --usepkgonly "$@"