Fix dartc.sh script to use /bin/bash (issue dart:1104)

compiler/scripts/dartc.sh

-#!/bin/sh
+#!/bin/bash --posix

[mmendez, 2012/01/10 14:27:01]

I'm not a scripting guru, but why does using bash fix the problem?  Isn't that
less standard?

[ricow1, 2012/01/10 14:34:07]

Here is the deal: On our normal linux boxes /bin/sh points at /bin/bash
ricow@nobby:~$ lsl /bin/sh
lrwxrwxrwx 1 root root 9 2010-10-01 14:46 /bin/sh -> /bin/bash

On the buildbot, it points at /bin/dash
chrome-bot@vm26-m3:~$ ls -l /bin/sh
lrwxrwxrwx 1 root root 4 2010-10-08 16:24 /bin/sh -> dash

Now, dash does not support the variable substitution inside a string, so that
will be an error!
I expect this to be the case for normal Ubuntu users as well

 # 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.
 
 SCRIPT_DIR=$(dirname $0)
 DARTC_HOME=$(dirname $SCRIPT_DIR)
 DARTC_LIBS=$DARTC_HOME/lib
 
 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.
   EXTRA_JVMARGS+="-Xmx256M"
 fi
 
 exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -classpath "@CLASSPATH@" \
   com.google.dart.compiler.DartCompiler $@