In linux-tick-processor only compile d8 if it doesn't exist.

tools/linux-tick-processor

Index: tools/linux-tick-processor
diff --git a/tools/linux-tick-processor b/tools/linux-tick-processor
index 0ad295f141eca930a4dfb876c9c3cc80e7cf73fd..e2f38b1b50530c32edc1c8d54cad1f903b213380 100755
--- a/tools/linux-tick-processor
+++ b/tools/linux-tick-processor
@@ -1,16 +1,16 @@
 #!/bin/sh
 
 tools_dir=$(dirname "$0")
+d8_exec=$tools_dir/../d8
 
-if [ "$1" != "--no-build" ]
+# compile d8 if it doesn't exist.
+if [ ! -x $d8_exec ]
 then
   scons -C $tools_dir/.. d8
-else
-  shift
 fi
 
-# nm spits out 'no symbols found' messages on stderr
-$tools_dir/../d8 $tools_dir/splaytree.js $tools_dir/codemap.js \
+# nm spits out 'no symbols found' messages to stderr.
+$d8_exec $tools_dir/splaytree.js $tools_dir/codemap.js \
   $tools_dir/csvparser.js $tools_dir/consarray.js \
   $tools_dir/profile.js $tools_dir/profile_view.js \
   $tools_dir/tickprocessor.js -- $@ 2>/dev/null