Add --jobs option to build_autotest.sh

src/scripts/build_autotest.sh

 #!/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.
 
 # This script makes autotest client tests inside a chroot environment.  The idea
 # is to compile any platform-dependent autotest client tests in the build
 # environment, since client systems under test lack the proper toolchain.
 #
 # The user can later run autotest against an ssh enabled test client system, or
 # install the compiled client tests directly onto the rootfs image.
 
 # Includes common already
 . "$(dirname $0)/autotest_lib.sh"
 
 # Script must be run inside the chroot
 assert_inside_chroot
 
 DEFAULT_TESTS_LIST="all"
 
 DEFINE_string build "${DEFAULT_TESTS_LIST}" \
   "a comma seperated list of autotest client tests to be prebuilt." b
 DEFINE_boolean prompt $FLAGS_TRUE "Prompt user when building all tests."
 DEFINE_boolean autox $FLAGS_TRUE "Build autox along with autotest"
 DEFINE_boolean buildcheck $FLAGS_TRUE "Fail if tests fail to build"
+DEFINE_integer jobs -1 "How many packages to build in parallel at maximum."
 
 # More useful help
 FLAGS_HELP="usage: $0 [flags]"
 
 # parse the command-line
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
 set -e
 
 check_board
 
+if [[ "${FLAGS_jobs}" -ne -1 ]]; then
+  EMERGE_JOBS="--jobs=${FLAGS_jobs}"
+fi
+
 # build default pre-compile client tests list.
 ALL_TESTS="compilebench,dbench,disktest,ltp,netperf2,unixbench"
 CLIENT_TEST_PATH="../third_party/autotest/files/client/site_tests"
 for SITE_TEST in ${CLIENT_TEST_PATH}/*
 do
   if [ -d ${SITE_TEST} ]
   then
     ALL_TESTS="${ALL_TESTS},${SITE_TEST##${CLIENT_TEST_PATH}/}"
   fi
 done
@@ skipping 34 matching lines @@
   TEST_LIST=${FLAGS_build}
 fi
 
 # Decide on USE flags based on options
 USE=
 [ $FLAGS_autox -eq "$FLAGS_FALSE" ] && USE="${USE} -autox"
 [ $FLAGS_buildcheck -eq "$FLAGS_TRUE" ] && USE="${USE} buildcheck"
 
 GCLIENT_ROOT="${GCLIENT_ROOT}" TEST_LIST=${TEST_LIST} \
   FEATURES="${FEATURES} -buildpkg" USE="$USE" "emerge-${FLAGS_board}" \
-  chromeos-base/autotest
+  chromeos-base/autotest ${EMERGE_JOBS}