Add symlink method to util.opener.
Differences from os.symlink:
- the symlink name is relative to the opener base directory
- if a file with that name already exists, it's removed
- if necessary, parent directories are created
- if the system (OS or filesystem) doesn't support symlinks, a
regular file is created. Its contents are the symlink target.
#header#
<title>Mercurial Error</title>
</head>
<body>
<h2>Mercurial Error</h2>
<p>
An error occured while processing your request:
</p>
<p>
#error|escape#
</p>
#footer#