--- firefox-78.2.0/python/mozbuild/mozbuild/virtualenv.py.orig	2020-09-15 21:32:27.365726770 +0200
+++ firefox-78.2.0/python/mozbuild/mozbuild/virtualenv.py	2020-09-15 21:37:16.580826624 +0200
@@ -63,8 +63,7 @@
     @property
     def virtualenv_script_path(self):
         """Path to virtualenv's own populator script."""
-        return os.path.join(self.topsrcdir, 'third_party', 'python',
-                            'virtualenv', 'virtualenv.py')
+        return '/usr/bin/virtualenv-3'
 
     @property
     def bin_path(self):