Turn NUM_JOBS into an overridable flag for distcc builds.

src/scripts/build_chrome.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.
 
 # Script for building our own custom Chrome
 
 # Load common constants.  This should be the first executable line.
 # The path to common.sh should be relative to your script's location.
 . "$(dirname "$0")/common.sh"
 
 # Script must be run outside the chroot
 assert_outside_chroot
 
 # This script defaults Chrome source is in ~/chrome
 # You may override the Chrome source dir via the --chrome_dir option or by 
 # setting CHROMEOS_CHROME_DIR (for example, in ./.chromeos_dev)
 DEFAULT_CHROME_DIR="${CHROMEOS_CHROME_DIR:-/home/$USER/chrome}"
 
+# The number of jobs to pass to tools that can run in parallel (such as make
+# and dpkg-buildpackage
+NUM_JOBS=`cat /proc/cpuinfo | grep processor | awk '{a++} END {print a}'`
+
 # Flags
 DEFINE_string chrome_dir "$DEFAULT_CHROME_DIR" \
   "Directory to Chrome source"
 DEFINE_string mode "Release" \
   "The mode to build Chrome in (Debug or Release)"
+DEFINE_string num_jobs "$NUM_JOBS" \
+  "The number of jobs to run in parallel"
 
 # Parse command line
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
 
 # Die on error; print commands
 set -e
 
 # Convert args to paths.  Need eval to un-quote the string so that shell
 # chars like ~ are processed; just doing FOO=`readlink -f $FOO` won't work.
 FLAGS_chrome_dir=`eval readlink -f $FLAGS_chrome_dir`
 
 # Build Chrome
 echo Building Chrome in mode $FLAGS_mode
-# The number of jobs to pass to tools that can run in parallel (such as make
-# and dpkg-buildpackage
-NUM_JOBS=`cat /proc/cpuinfo | grep processor | awk '{a++} END {print a}'`
 export GYP_GENERATORS="make"
 export GYP_DEFINES="chromeos=1 target_arch=ia32"
 CHROME_DIR=$FLAGS_chrome_dir
 cd "$CHROME_DIR/src"
 gclient runhooks --force
-make BUILDTYPE=$FLAGS_mode -j$NUM_JOBS -r chrome
+make BUILDTYPE=$FLAGS_mode -j$FLAGS_num_jobs -r chrome
 
 # Zip into chrome-chromeos.zip and put in local_assets
 BUILD_DIR="$CHROME_DIR/src/out"
 CHROME_LINUX_DIR="$BUILD_DIR/chrome-chromeos"
 OUTPUT_DIR="${SRC_ROOT}/build/x86/local_assets"
 OUTPUT_ZIP="$BUILD_DIR/chrome-chromeos.zip"
 if [ -n "$OUTPUT_DIR" ]
 then
   mkdir -p $OUTPUT_DIR
 fi
 # create symlink so that we can create the zip file with prefix chrome-chromeos
 rm -f $CHROME_LINUX_DIR
 ln -s $BUILD_DIR/$FLAGS_mode $CHROME_LINUX_DIR
 
 echo Zipping $CHROME_LINUX_DIR to $OUTPUT_ZIP
 cd $BUILD_DIR
 rm -f $OUTPUT_ZIP
 zip -r9 $OUTPUT_ZIP chrome-chromeos -i "chrome-chromeos/chrome*" \
   "chrome-chromeos/libffmpegsumo.so" "chrome-chromeos/xdg-settings" \
   "chrome-chromeos/locales/*" "chrome-chromeos/resources/*" \
   "chrome-chromeos/*.png" -x "*.d"
 cp -f $OUTPUT_ZIP $OUTPUT_DIR
 echo Done.