@@ -, +, @@ 
---
 pip/commands/install.py | 3 +++
 1 file changed, 3 insertions(+)
--- a/pip/commands/install.py	
+++ a/pip/commands/install.py	
@@ -204,6 +204,9 @@ class InstallCommand(RequirementCommand):
             )
             options.ignore_installed = True
 
+        if not options.use_user_site and not options.target_dir and not options.root_path:
+            raise CommandError("(Gentoo) Please run pip with the --user option to avoid breaking python-exec")
+
         if options.build_dir:
             options.build_dir = os.path.abspath(options.build_dir)
 
--