dev-python/citeproc-py: fix build with python3

Closes: https://bugs.gentoo.org/659520
Package-Manager: Portage-2.3.49, Repoman-2.3.10

dev-python/citeproc-py/citeproc-py-0.4.0.ebuild

@@ -15,6 +15,8 @@ SLOT="0"
 KEYWORDS="~amd64 ~x86"
 IUSE=""
 
+PATCHES=( "${FILESDIR}/b1a5f925527093b0b5c11507f379a908e3354820.patch" )
+
 DEPEND="
 	dev-python/rnc2rng[${PYTHON_USEDEP}]
 	dev-python/lxml[${PYTHON_USEDEP}]"

dev-python/citeproc-py/files/b1a5f925527093b0b5c11507f379a908e3354820.patch

@@ -0,0 +1,42 @@
+From b1a5f925527093b0b5c11507f379a908e3354820 Mon Sep 17 00:00:00 2001
+From: Brecht Machiels <brecht@mos6581.org>
+Date: Tue, 22 May 2018 12:57:47 +0200
+Subject: [PATCH] rnc2rng 2.6.1 handles rnc file encoding (fixes #81)
+
+---
+ setup.py | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/setup.py b/setup.py
+index dbaad6d..774932b 100755
+--- a/setup.py
++++ b/setup.py
+@@ -9,6 +9,7 @@
+ import sys
+ 
+ from datetime import datetime
++from io import open
+ from subprocess import Popen, PIPE
+ from setuptools import setup, find_packages
+ from setuptools.command.build_py import build_py
+@@ -63,9 +64,8 @@ def convert_rnc():
+     import rnc2rng
+ 
+     filename_root, _ = os.path.splitext(CSL_SCHEMA_RNC)
+-    with open(CSL_SCHEMA_RNC, 'r') as rnc:
+-        root = rnc2rng.load(rnc)
+-    with open(filename_root + '.rng', 'w') as rng:
++    root = rnc2rng.load(CSL_SCHEMA_RNC)
++    with open(filename_root + '.rng', 'w', encoding='utf-8') as rng:
+         rnc2rng.dump(root, rng)
+ 
+ 
+@@ -91,7 +91,7 @@ def run(self):
+                             'data/schema/*.rng',
+                             'data/styles/*.csl']},
+     scripts=['bin/csl_unsorted'],
+-    setup_requires=['rnc2rng>=2.2'],
++    setup_requires=['rnc2rng>=2.6.1'],
+     install_requires=['lxml'],
+     provides=[PACKAGE],
+     #test_suite='nose.collector',