From http://deb.debian.org/debian/pool/main/0/0ad/0ad_0.0.26-5.debian.tar.xz

Index: libraries/source/spidermonkey/0001-Python-Build-Use-r-instead-of-rU-file-read-modes.patch
--- libraries/source/spidermonkey/0001-Python-Build-Use-r-instead-of-rU-file-read-modes.patch.orig
+++ libraries/source/spidermonkey/0001-Python-Build-Use-r-instead-of-rU-file-read-modes.patch
@@ -0,0 +1,81 @@
+From 95f1e91ef71d912be5f6dddb6fac68671d850fd6 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Franti=C5=A1ek=20Zatloukal?= <fzatlouk@redhat.com>
+Date: Sun, 24 Jul 2022 11:11:01 +0200
+Subject: [PATCH] Python/Build: Use r instead of rU file read modes
+
+Fixes Python 3.11 build
+---
+ python/mozbuild/mozbuild/action/process_define_files.py | 2 +-
+ python/mozbuild/mozbuild/preprocessor.py                | 6 +++---
+ python/mozbuild/mozbuild/util.py                        | 4 +++-
+ 3 files changed, 7 insertions(+), 5 deletions(-)
+
+diff --git a/python/mozbuild/mozbuild/action/process_define_files.py b/python/mozbuild/mozbuild/action/process_define_files.py
+index 6fff0d1..de2bcf4 100644
+--- a/python/mozbuild/mozbuild/action/process_define_files.py
++++ b/python/mozbuild/mozbuild/action/process_define_files.py
+@@ -36,7 +36,7 @@ def process_define_file(output, input):
+             not config.substs.get('JS_STANDALONE'):
+         config = PartialConfigEnvironment(mozpath.join(topobjdir, 'js', 'src'))
+ 
+-    with open(path, 'rU') as input:
++    with open(path, 'r') as input:
+         r = re.compile('^\s*#\s*(?P<cmd>[a-z]+)(?:\s+(?P<name>\S+)(?:\s+(?P<value>\S+))?)?', re.U)
+         for l in input:
+             m = r.match(l)
+diff --git a/python/mozbuild/mozbuild/preprocessor.py b/python/mozbuild/mozbuild/preprocessor.py
+index 0e3a750..66f5cf7 100644
+--- a/python/mozbuild/mozbuild/preprocessor.py
++++ b/python/mozbuild/mozbuild/preprocessor.py
+@@ -517,7 +517,7 @@ class Preprocessor:
+ 
+         if args:
+             for f in args:
+-                with io.open(f, 'rU', encoding='utf-8') as input:
++                with io.open(f, 'r', encoding='utf-8') as input:
+                     self.processFile(input=input, output=out)
+             if depfile:
+                 mk = Makefile()
+@@ -807,7 +807,7 @@ class Preprocessor:
+                     args = self.applyFilters(args)
+                 if not os.path.isabs(args):
+                     args = os.path.join(self.curdir, args)
+-                args = io.open(args, 'rU', encoding='utf-8')
++                args = io.open(args, 'r', encoding='utf-8')
+             except Preprocessor.Error:
+                 raise
+             except Exception:
+@@ -862,7 +862,7 @@ def preprocess(includes=[sys.stdin], defines={},
+     pp = Preprocessor(defines=defines,
+                       marker=marker)
+     for f in includes:
+-        with io.open(f, 'rU', encoding='utf-8') as input:
++        with io.open(f, 'r', encoding='utf-8') as input:
+             pp.processFile(input=input, output=output)
+     return pp.includes
+ 
+diff --git a/python/mozbuild/mozbuild/util.py b/python/mozbuild/mozbuild/util.py
+index 044cf64..eb992ce 100644
+--- a/python/mozbuild/mozbuild/util.py
++++ b/python/mozbuild/mozbuild/util.py
+@@ -54,6 +54,8 @@ def exec_(object, globals=None, locals=None):
+ 
+ 
+ def _open(path, mode):
++    if mode == "rU":
++        mode = "r"
+     if 'b' in mode:
+         return io.open(path, mode)
+     return io.open(path, mode, encoding='utf-8', newline='\n')
+@@ -220,7 +222,7 @@ class FileAvoidWrite(BytesIO):
+     still occur, as well as diff capture if requested.
+     """
+ 
+-    def __init__(self, filename, capture_diff=False, dry_run=False, readmode='rU'):
++    def __init__(self, filename, capture_diff=False, dry_run=False, readmode='r'):
+         BytesIO.__init__(self)
+         self.name = filename
+         assert type(capture_diff) == bool
+-- 
+2.37.1
+
