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

sdk/bin/dart2js

 #!/bin/bash
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # 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"
 
 DART="$BIN_DIR/dart"
 
 SNAPSHOT_DIR="$BIN_DIR/snapshots"
 SNAPSHOT="$SNAPSHOT_DIR/utils_wrapper.dart.snapshot"
 
 unset EXTRA_OPTIONS
 declare -a EXTRA_OPTIONS
@@ skipping 24 matching lines @@
     EXTRA_VM_OPTIONS[${#EXTRA_VM_OPTIONS[@]}]='--checked'
     ;;
 esac
 
 if test -f "$SNAPSHOT"; then
   exec "$DART" "${EXTRA_VM_OPTIONS[@]}" "$SNAPSHOT" "dart2js" \
       "${EXTRA_OPTIONS[@]}" "$@"
 else
   exec "$DART" "${EXTRA_VM_OPTIONS[@]}" "$DART2JS" "${EXTRA_OPTIONS[@]}" "$@"
 fi