--- a/libbuild2/buildfile
+++ b/libbuild2/buildfile
@@ -73,7 +73,11 @@ config/cxx{host-config}: config/in{host-config}
   #
   build2_config = $regex.replace_lines(                              \
+    $regex.replace_lines(                                            \
     $config.save(),                                                  \
     '^ *(#|(config\.(dist\.|install\.chroot|config\.hermetic))).*$', \
     [null],                                                          \
+    return_lines),                                                   \
+    '^.*'$getenv(NIX_STORE)'/[a-z0-9]{32}-.*$',                      \
+    [null],                                                          \
     return_lines)