Fix paths in build process so we can build dartc (and then frog) on Windows.

compiler/generate_source_list.py

 #!/usr/bin/env python
 # 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.
 
 from __future__ import with_statement
 import StringIO
 import os
 import sys
 
@@ skipping 36 matching lines @@
         elif (filename.endswith('.pyc')):
           pass
         else:
           self.resources.append(os.path.join(path, filename))
     self.sources.sort()
     self.resources.sort()
 
   def _print_gypi_files(self, out, name, files):
     out.write("    '%s': [\n" % name)
     for filename in files:
-      out.write('''      r'%s',%s''' % (os.path.join(self.path, filename),'\n'))
+      out.write('''      r'%s/%s',%s''' % (self.path, filename,'\n'))
     out.write("    ],\n")
 
   def _print_ant_files(self, out, name, files):
     out.write("  <filelist id='%s' dir='%s'>\n" % (name, self.path))
     for filename in files:
       out.write("    <file name='%s'/>\n" % filename)
     out.write("  </filelist>\n")
     out.write("  <pathconvert pathsep=',' property='%s' refid='%s'>\n"
               % (name, name))
     out.write("    <map from='${basedir}/%s/' to=''/>\n" % self.path)
@@ skipping 41 matching lines @@
          *rest):
   if not path:
     raise GenerateError("usage: %s NAME OUTPUT PATH EXCLUDE_DIR_NAME ..."
                         % script_name)
   base_directory = os.path.dirname(output)
   Generator(base_directory, name, output, path, *rest).generate()
 
 
 if __name__ == '__main__':
   sys.exit(Main(*sys.argv))