Use read_file instead of deprecated readfp  - removed in Python 3.11 

diff -ur subversion-1.14.1/build/generator/gen_base.py subversion-1.14.1-patched/build/generator/gen_base.py
--- subversion-1.14.1/build/generator/gen_base.py	2019-11-04 06:59:36.000000000 +0100
+++ subversion-1.14.1-patched/build/generator/gen_base.py	2021-12-15 14:04:50.041649320 +0100
@@ -76,7 +76,7 @@
 
     # Now read and parse build.conf
     parser = configparser.ConfigParser()
-    parser.readfp(open(fname))
+    parser.read_file(open(fname))
 
     self.conf = build_path(os.path.abspath(fname))