Fix path to d8 and properly quote strings so it works with dash(1)

tools/linux-tick-processor

Index: tools/linux-tick-processor
diff --git a/tools/linux-tick-processor b/tools/linux-tick-processor
index 7070ce6fcc9a5aef8c75a25f3ff5b8ba328b8033..93f143f9a95b39a77c73c47d312cef05650552d0 100755
--- a/tools/linux-tick-processor
+++ b/tools/linux-tick-processor
@@ -12,21 +12,21 @@ done
 tools_path=`cd $(dirname "$0");pwd`
 if [ ! "$D8_PATH" ]; then
   d8_public=`which d8`
-  if [ -x $d8_public ]; then D8_PATH=$(dirname "$d8_public"); fi
+  if [ -x "$d8_public" ]; then D8_PATH=$(dirname "$d8_public"); fi
 fi
-[ "$D8_PATH" ] || D8_PATH=$tools_path/..
+[ -n "$D8_PATH" ] || D8_PATH=$tools_path/..
 d8_exec=$D8_PATH/d8
 
-if [ ! -x $d8_exec ]; then
+if [ ! -x "$d8_exec" ]; then
   D8_PATH=`pwd`/out/native
   d8_exec=$D8_PATH/d8
 fi
 
-if [ ! -x $d8_exec ]; then
+if [ ! -x "$d8_exec" ]; then
   d8_exec=`grep -m 1 -o '".*/d8"' $log_file | sed 's/"//g'`
 fi
 
-if [ ! -x $d8_exec ]; then
+if [ ! -x "$d8_exec" ]; then
   echo "d8 shell not found in $D8_PATH"
   echo "To build, execute 'make native' from the V8 directory"
   exit 1