Turn NUM_JOBS into an overridable flag for distcc builds.

src/scripts/build_chrome.sh

Index: src/scripts/build_chrome.sh
diff --git a/src/scripts/build_chrome.sh b/src/scripts/build_chrome.sh
index a482d2945e09ee5fa186a067a471c0fe442a0f8a..d693edc0dee67399a8b95a0350550b28c3cfeb8a 100755
--- a/src/scripts/build_chrome.sh
+++ b/src/scripts/build_chrome.sh
@@ -18,11 +18,17 @@ assert_outside_chroot
 # 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
@@ -37,15 +43,12 @@ 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"