Fix setuptools bootstrapping now that dependencies are no longer vendored (#3198)

* Fix setuptools bootstrapping now that dependencies are no longer vendored
* Reorder patch and comments
* Use exact same patch as https://github.com/ActiveState/appdirs/pull/84
* Use exact same patch as https://sourceforge.net/p/pyparsing/patches/10/

var/spack/repos/builtin/packages/py-appdirs/package.py

@@ -0,0 +1,44 @@
+##############################################################################
+# Copyright (c) 2013-2016, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+
+
+class PyAppdirs(PythonPackage):
+    """A small Python module for determining appropriate platform-specific
+    dirs, e.g. a "user data dir"."""
+
+    homepage = "https://github.com/ActiveState/appdirs"
+    url      = "https://pypi.io/packages/source/a/appdirs/appdirs-1.4.0.tar.gz"
+
+    version('1.4.0', '1d17b4c9694ab84794e228f28dc3275b')
+
+    patch('setuptools-import.patch', when='@:1.4.0')
+
+    # Newer versions of setuptools require appdirs. Although setuptools is an
+    # optional dependency of appdirs, if it is not found, setup.py will
+    # fallback on distutils.core instead. Don't add a setuptools dependency
+    # or we won't be able to bootstrap setuptools.
+
+    # depends_on('py-setuptools', type='build')

var/spack/repos/builtin/packages/py-appdirs/setuptools-import.patch

@@ -0,0 +1,17 @@
+diff --git a/setup.py b/setup.py
+index ccd1e72..5d907aa 100644
+--- a/setup.py
++++ b/setup.py
+@@ -2,7 +2,12 @@
+ import sys
+ import os
+ import os.path
+-from setuptools import setup
++# appdirs is a dependency of setuptools, so allow installing without it.
++try:
++    from setuptools import setup
++except ImportError:
++    from distutils.core import setup
+ import appdirs
+ 
+ tests_require = []