Optionally use setuptools if it is installed.

Thanks to to github.com/roryk for the suggestion.

(imported from commit 9e4365dc56f1bc2f1a1a49be4a7b662d94bf42a9)

setup.py

@@ -4,7 +4,6 @@
 import zulip
 
 import os
-from distutils.core import setup
 import sys
 
 import itertools
@@ -23,11 +22,13 @@ def recur_expand(target_root, dir):
     if len(paths):
       yield os.path.join(target_root, root), paths
 
-setup(name='zulip',
+# We should be installable with either setuptools or distutils.
+package_info = dict(
+    name='zulip',
     version=version(),
     description='Bindings for the Zulip message API',
     author='Zulip, Inc.',
-      author_email='zulip@zulip.com',
+    author_email='humbug@humbughq.com',
     classifiers=[
         'Development Status :: 3 - Alpha',
         'Environment :: Web Environment',
@@ -44,3 +45,31 @@ setup(name='zulip',
         list(recur_expand('share/zulip', 'integrations/')),
     scripts=["bin/zulip-send"],
 )
+
+setuptools_info = dict(
+    install_requires=['requests>=0.12.1',
+                      'simplejson',
+    ],
+)
+
+try:
+  from setuptools import setup
+  package_info.update(setuptools_info)
+except ImportError:
+  from distutils.core import setup
+  from distutils.version import LooseVersion
+  # Manual dependency check
+  try:
+    import simplejson
+  except ImportError:
+    print >>sys.stderr, "simplejson is not installed"
+    sys.exit(1)
+  try:
+    import requests
+    assert(LooseVersion(requests.__version__) >= LooseVersion('0.12.1'))
+  except (ImportError, AssertionError):
+    print >>sys.stderr, "requests >=0.12.1 is not installed"
+    sys.exit(1)
+
+
+setup(**package_info)