Make it possible to symlink to dartdoc and pub in the SDK.

sdk/bin/dart2js

Index: sdk/bin/dart2js
diff --git a/sdk/bin/dart2js b/sdk/bin/dart2js
index 2baaba762ffef2f09f8722b7fe25e6cdd24faaef..9c9e7cd880c8945a283472905a83bada04866fa1 100755
--- a/sdk/bin/dart2js
+++ b/sdk/bin/dart2js
@@ -4,20 +4,19 @@
 # BSD-style license that can be found in the LICENSE file.
 
 function follow_links() {
-  while [ -h "$1" ]; do
+  file="$1"
+  while [ -h "$file" ]; do
     # On Mac OS, readlink -f doesn't work.
-    1="$(readlink "$1")"
+    file="$(readlink "$file")"
   done
-  echo "$1"
+  echo "$(cd "$(dirname $file)"; pwd -P)/$(basename "$file")"
 }
 
-# Unlike $0, $BASH_SOURCE points to the absolute path of this file.
-PROG_NAME="$(follow_links "$BASH_SOURCE")"
-
-# Handle the case where dart-sdk/bin has been symlinked to.
-BIN_DIR="$(follow_links "$(cd "${PROG_NAME%/*}" ; pwd -P)")"
-
-SDK_DIR="$(cd "${BIN_DIR}/.." ; pwd -P)"
+# Unlike $0, $BASH_SOURCE points to the absolute path of this file. Follow
+# symlinks to handle the case where dart-sdk/bin or dart-sdk/bin/dart2js have
+# been linked to.
+BIN_DIR="$(dirname "$(follow_links "$BASH_SOURCE")")"
+SDK_DIR="$(dirname "$BIN_DIR")"
 
 DART2JS="$SDK_DIR/lib/_internal/compiler/implementation/dart2js.dart"