diff -upr mapnik-v3.1.0.orig/SConstruct mapnik-v3.1.0/SConstruct
--- mapnik-v3.1.0.orig/SConstruct	2021-01-08 13:23:24.000000000 +0200
+++ mapnik-v3.1.0/SConstruct	2021-11-22 11:41:03.413991679 +0200
@@ -126,7 +126,6 @@ PLUGINS = { # plugins with external depe
 
 def init_environment(env):
     env.Decider('MD5-timestamp')
-    env.SourceCode(".", None)
     if os.environ.get('RANLIB'):
         env['RANLIB'] = os.environ['RANLIB']
     if os.environ.get('AR'):