Port py3 module away from deprecated imp

PKGBUILD

@@ -2,7 +2,7 @@
 
 pkgname=brial
 pkgver=1.2.5
-pkgrel=3
+pkgrel=4
 pkgdesc="Library for polynomials over boolean rings"
 arch=(x86_64)
 url="https://github.com/BRiAl/BRiAl"
@@ -10,11 +10,16 @@ license=(GPL)
 depends=(m4ri)
 makedepends=(boost python python2)
 optdepends=('python: Python 3 bindings' 'python2: Python 2 bindings')
-source=("https://github.com/BRiAl/BRiAl/releases/download/$pkgver/brial-$pkgver.tar.bz2")
-sha256sums=('c4921d5008ac9122452e6f93abb696ef21ceac8e7170008ea7c7b05508da8d34')
+source=("https://github.com/BRiAl/BRiAl/releases/download/$pkgver/brial-$pkgver.tar.bz2"
+        brial-imp.patch)
+sha256sums=('c4921d5008ac9122452e6f93abb696ef21ceac8e7170008ea7c7b05508da8d34'
+            '2f16ac32f905980ea49e2a4cdc7d44a3eec4d794e4cbde24a583a8d1045df2f8')
 
 prepare() {
   cp -r $pkgname-$pkgver/sage-brial{,-py2}
+
+  cd $pkgname-$pkgver/sage-brial
+  patch -p1 -i "$srcdir"/brial-imp.patch # For away from deprecated imp module
 }
 
 build() {

brial-imp.patch

+--- sage-brial/brial/gbrefs.py.orig	2019-09-01 22:09:29.585226434 +0000
++++ sage-brial/brial/gbrefs.py	2019-09-01 22:10:49.416270516 +0000
+@@ -6,7 +6,7 @@
+     from io import StringIO
+ import uu
+ import re
+-import imp
++import types
+ from .PyPolyBoRi import *
+ AUTO = "auto"
+ SINGLE = "single"
+@@ -118,7 +118,7 @@
+ 
+ 
+ def dyn_generate(content, name):
+-    module = imp.new_module(name)
++    module = types.ModuleType(name)
+     import_header = """from .PyPolyBoRi import Variable,Monomial, Polynomial, Ring, OrderCode
+ from itertools import chain
+ from .blocks import AlternatingBlock,Block,AdderBlock,if_then,HigherOrderBlock,declare_ring as orig_declare_ring,declare_block_scheme,MacroBlock\n