Mention KCONFIG_STRICT in the README

Also fix up Kconfig.__init__() docstring to say that KCONFIG_STRICT
needs to be "y".

1 files changed, 14 insertions, 3 deletions

diff --git a/README.rst b/README.rst
index 2af9e9f..94aeba7 100644
--- a/README.rst
+++ b/README.rst
@@ -8,7 +8,7 @@ Kconfiglib is a `Kconfig
 <https://www.kernel.org/doc/Documentation/kbuild/kconfig-language.txt>`_
 implementation in Python 2/3. It started out as a helper library, but now has a
 enough functionality to also work well as a standalone Kconfig implementation
-(including ``menuconfig`` implementations).
+(including `menuconfig interfaces`_ and `Kconfig extensions`_).
 
 The entire library is contained in `kconfiglib.py
 <https://github.com/ulfalizer/Kconfiglib/blob/master/kconfiglib.py>`_. The
@@ -191,8 +191,8 @@ Kconfiglib can do the following, among other things:
   <https://github.com/ulfalizer/Kconfiglib/blob/master/examples/menuconfig_example.py>`_
   example.
 
-Kconfig language extensions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Kconfig extensions
+~~~~~~~~~~~~~~~~~~
 
 The following Kconfig extensions are available:
 
@@ -224,6 +224,15 @@ The following Kconfig extensions are available:
   caveat that they must have the same name as the environment variables they
   reference. A warning is printed if the names differ.
 
+- Setting the environment variable ``KCONFIG_STRICT`` to "y" will cause warnings to be printed
+  for all references to undefined Kconfig symbols within Kconfig files. The only gotcha is
+  that all ``hex`` literals must be prefixed by "0x" or "0X", to make it possible to distuinguish
+  them from symbol references.
+
+  Some projects (e.g. the Linux kernel) use multiple Kconfig trees with many shared ``Kconfig``
+  files, leading to some safe undefined symbol references. ``KCONFIG_STRICT`` is useful in
+  projects that only have a single ``Kconfig`` tree though.
+
 Other features
 --------------
 
@@ -297,6 +306,8 @@ Other features
   
   While being simpler to understand and tweak.
 
+.. menuconfig_implementations:
+
 Menuconfig interfaces
 ---------------------