Removes dartc reliance on its own libraries, now can be targeted at any implementation's libraries

compiler/scripts/darta.sh

 #!/bin/bash --posix
 # Copyright (c) 2011, 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.
 
 set -e
 
 SCRIPT_DIR=$(dirname $0)
-DARTC_HOME=$(dirname $SCRIPT_DIR)
-DARTC_LIBS=$DARTC_HOME/lib
+DARTA_HOME=${SCRIPT_DIR}
+# Assuming running from dart-sdk/analysis
+DART_LIBDIR=${SCRIPT_DIR}/..
+
+# Make sure the libdir looks right. 
+if [ ! -f ${DART_LIBDIR}/core/lib/core/core_runtime.dart -a -d ${DART_LIBDIR}/dart-sdk ] ; then
+  # for running from out/<arch>/analysis
+  DART_LIBDIR=${DART_LIBDIR}/dart-sdk
+fi
 
 if [ -x /usr/libexec/java_home ]; then
   export JAVA_HOME=$(/usr/libexec/java_home -v '1.6+')
 fi
 
 EXTRA_JVMARGS="-Xss2M "
 OS=`uname | tr [A-Z] [a-z]`
 if [ "$OS" == "darwin" ] ; then
   # Bump up the heap on Mac VMs, some of which default to 128M or less.
   # Users can specify DART_JVMARGS in the environment to override
   # this setting. Force to 32 bit client vm. 64 bit and server VM make for 
   # poor performance.
   EXTRA_JVMARGS+="-Xmx256M -client -d32"
 fi
 
-exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -classpath "@CLASSPATH@" \
-  com.google.dart.compiler.DartCompiler $@
+
+CLASSPATH="@CLASSPATH@"
+exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -classpath $CLASSPATH \
+  com.google.dart.compiler.DartCompiler --dart-sdk ${DART_LIBDIR} $@
+