Ensure proper path traversals for linked commands;

sdk/bin/dartanalyzer

Index: sdk/bin/dartanalyzer
diff --git a/sdk/bin/dartanalyzer b/sdk/bin/dartanalyzer
index 3f0f947c1e9bca805031fa7c772674857663ff10..af3656b56a7cf0336dfed28ff3821e3e8d21521b 100755
--- a/sdk/bin/dartanalyzer
+++ b/sdk/bin/dartanalyzer
@@ -8,8 +8,18 @@ set -e
 # Setting SCRIPT_DIR this way is ugly, but is needed to handle the case where
 # dart-sdk/bin has been symlinked to. On MacOS, readlink doesn't work
 # with this case.
-SCRIPT_DIR="$(cd "${0%/*}" ; pwd -P)"
-DART_ANALYZER_HOME="$(cd "${SCRIPT_DIR%/*}" ; pwd -P)"
+function link_dir() {
+  a="$1"
+  while [ -h "$a" ]; do
+    # On Mac OS, readlink -f doesn't work.
+    a="$(readlink "$a")"
+  done
+  # if dir linked, not file, need to follow dir path:
+  echo $(cd $(dirname $a); pwd -P)
+}
+
+SCRIPT_DIR="$(link_dir "$0")"
+DART_ANALYZER_HOME="${SCRIPT_DIR%/*}"
 
 FOUND_BATCH=0
 FOUND_SDK=0