Added py3dns recipe (#2590)

* Added py3dns recipe
* Update py3dns recipe

pythonforandroid/recipes/py3dns/__init__.py

@@ -0,0 +1,13 @@
+from pythonforandroid.recipe import PythonRecipe
+
+
+class Py3DNSRecipe(PythonRecipe):
+    site_packages_name = 'DNS'
+    version = '3.2.1'
+    url = 'https://launchpad.net/py3dns/trunk/{version}/+download/py3dns-{version}.tar.gz'
+    depends = ['setuptools']
+    patches = ['patches/android.patch']
+    call_hostpython_via_targetpython = False
+
+
+recipe = Py3DNSRecipe()

pythonforandroid/recipes/py3dns/patches/android.patch

@@ -0,0 +1,27 @@
+diff --git a/DNS/Base.py b/DNS/Base.py
+index 34a6da7..a558889 100644
+--- a/DNS/Base.py
++++ b/DNS/Base.py
+@@ -15,6 +15,7 @@ import socket, string, types, time, select
+ import errno
+ from . import Type,Class,Opcode
+ import asyncore
++import os
+ #
+ # This random generator is used for transaction ids and port selection.  This
+ # is important to prevent spurious results from lost packets, and malicious
+@@ -50,8 +51,12 @@ defaults= { 'protocol':'udp', 'port':53, 'opcode':Opcode.QUERY,
+
+ def ParseResolvConf(resolv_path="/etc/resolv.conf"):
+     "parses the /etc/resolv.conf file and sets defaults for name servers"
+-    with open(resolv_path, 'r') as stream:
+-        return ParseResolvConfFromIterable(stream)
++    if os.path.exists(resolv_path):
++        with open(resolv_path, 'r') as stream:
++            return ParseResolvConfFromIterable(stream)
++    else:
++        defaults['server'].append('127.0.0.1')
++        return
+
+ def ParseResolvConfFromIterable(lines):
+     "parses a resolv.conf formatted stream and sets defaults for name servers"