env_update: document ldconfig -X for bug #373341

diff --git a/pym/portage/util/env_update.py b/pym/portage/util/env_update.py
index a82afdfea3c599e74f49d3564f373ba11231f804..3e295f00bb0214c0c5d95150254cbeb778baa82c 100644 (file)
--- a/pym/portage/util/env_update.py
+++ b/pym/portage/util/env_update.py
@@ -27,7 +27,14 @@ def env_update(makelinks=1, target_root=None, prev_mtimes=None, contents=None,
        env=None, writemsg_level=None):
        """
        Parse /etc/env.d and use it to generate /etc/profile.env, csh.env,
-       ld.so.conf, and prelink.conf. Finally, run ldconfig.
+       ld.so.conf, and prelink.conf. Finally, run ldconfig. When ldconfig is
+       called, its -X option will be used in order to avoid potential
+       interference with installed soname symlinks that are required for
+       correct operation of FEATURES=preserve-libs for downgrade operations.
+       It's not necessary for ldconfig to create soname symlinks, since
+       portage will use NEEDED.ELF.2 data to automatically create them
+       after src_install if they happen to be missing.
+       @param makelinks: True if ldconfig should be called, False otherwise
        @param target_root: root that is passed to the ldconfig -r option,
                defaults to portage.settings["ROOT"].
        @type target_root: String (Path)