diff --git a/distutils/command/install.py b/distutils/command/install.py
index d648dd18..c97e1eb3 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -190,9 +190,6 @@ class install(Command):
 
     negative_opt = {'no-compile' : 'compile'}
 
-    # Allow Fedora to add components to the prefix
-    _prefix_addition = getattr(sysconfig, '_prefix_addition', "")
-
     def initialize_options(self):
         """Initializes options."""
         # High-level options: these select both an installation base
@@ -473,10 +470,13 @@ def finalize_unix(self):
                     raise DistutilsOptionError(
                           "must not supply exec-prefix without prefix")
 
+                # Allow Fedora to add components to the prefix
+                _prefix_addition = getattr(sysconfig, '_prefix_addition', "")
+
                 self.prefix = (
-                    os.path.normpath(sys.prefix) + self._prefix_addition)
+                    os.path.normpath(sys.prefix) + _prefix_addition)
                 self.exec_prefix = (
-                    os.path.normpath(sys.exec_prefix) + self._prefix_addition)
+                    os.path.normpath(sys.exec_prefix) + _prefix_addition)
 
             else:
                 if self.exec_prefix is None: