[PATCH] Documentation: Update env sources documentation

[Trent Piepho]

Add CONFIG_DEFAULT_ENVIRONMENT_PATH to the list in the proper place.

Update the board env to follow the new pattern for naming and note that,
unlike the other directories, one must add code to get this directory in
the environment.
---
 Documentation/user/defaultenv-2.rst | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/Documentation/user/defaultenv-2.rst b/Documentation/user/defaultenv-2.rst
index da766e4ed..bf738084b 100644
--- a/Documentation/user/defaultenv-2.rst
+++ b/Documentation/user/defaultenv-2.rst
@@ -19,14 +19,18 @@ All new boards should use defaultenv-2 exclusively.
 
 The default environment is composed from different directories during compilation::
 
-  defaultenv/defaultenv-2-base        -> base files
-  defaultenv/defaultenv-2-dfu         -> overlay for DFU
-  defaultenv/defaultenv-2-reboot-mode -> overlay for reboot modes
-  defaultenv/defaultenv-2-menu        -> overlay for menus
-  arch/$ARCH/boards/<board>/env       -> board specific overlay
+  defaultenv/defaultenv-2-base                 -> base files
+  defaultenv/defaultenv-2-dfu                  -> overlay for DFU
+  defaultenv/defaultenv-2-reboot-mode          -> overlay for reboot modes
+  defaultenv/defaultenv-2-menu                 -> overlay for menus
+  arch/$ARCH/boards/<board>/defaultenv-<board> -> board specific overlay
+  $(CONFIG_DEFAULT_ENVIRONMENT_PATH)           -> config specific overlay
 
 The content of the above directories is applied one after another. If the
-same file exists in a later overlay, it will overwrite the preceding one.
+same file exists in a later overlay, it will overwrite the preceding one.  The
+board specific overlay, or overlays, could be at any path, but usually follows
+the form given.  They must be added to a Makefile in ``bbenv-y`` and
+``defaultenv_append_directory()`` used to add them in board init code.
 
 Note that not all of the above directories will necessarily be
 included in your default environment, it depends on your barebox
-- 
2.26.2