diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index 0dc472e3c7b..b51d57f079f 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -47,6 +47,7 @@
             %binary-format-file-system
             %shared-memory-file-system
             %pseudo-terminal-file-system
+            %tty-gid
             %immutable-store
             %control-groups
             %elogind-file-systems
diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index 705943eb73d..adeceb4a890 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -33,6 +33,8 @@
   #:export (%python-build-system-modules
             package-with-python2
             strip-python2-variant
+            default-python
+            default-python2
             python-build
             python-build-system
             pypi-uri))