More CMake documentation

actions/CMakeLists.txt

 add_custom_target(actions ALL)
+add_subdirectory(tests)
+
 pm_action_init()
 pm_action(pm-build-rawmodel actions)
 pm_action(pm-help actions)
-
-add_subdirectory(tests)

cmake_support/doc/index.rst

@@ -26,7 +26,7 @@ into three categories of varying relevance for you:
 Best practices for using our home-brew |cmake| functions are found in the
 various :file:`CMakeLists.txt` files in the project's directory tree.
 
-Functions For Module Maintenance
+Functions For Module/ Action Maintenance
 --------------------------------------------------------------------------------
 
 Unit Tests
@@ -54,7 +54,8 @@ Unit Tests
 
   ``MODULE``
     Specify the name of the module these tests are made for. Needs to be set,
-    needs to be a single word.
+    needs to be a single word. Ends up in ``make help`` as a prefix, nothing
+    will break if it does not match the name of any existing module.
 
   ``Sources``
     Describe a set of files hosting unit test code here. If its a wild mix of
@@ -80,10 +81,36 @@ Unit Tests
   ``TARGET``
     This defines an additional dependency for the unit test.
 
+Actions
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+.. cmake:command:: pm_action
+
+  .. code-block:: cmake
+
+                  pm_action(ACTION action-script
+                            TARGET target)
+
+  Add an action to |project|. Actions are scripts called by the ``pm`` launcher
+  and should all live in the :file:`actions` directory as executable files.
+  Adding an action means connecting its file with the given target to be copied
+  to the :file:`libexec` directory. No dedicated ``make`` target will be
+  created.
+
+  The parameters are:
+
+  ``ACTION``
+    Name of the action to be added. Should start with ``pm-``. Needs to be an
+    existing file in the same directory as the invoking :file:`CMakeLists.txt`.
+
+  ``TARGET``
+    Provide a ``make`` target to trigger copying the action's script file. The
+    target has to be created **before** any action may be attached to it.
+
 .. Finding packages
 .. -----------------
 
 .. Extending |cmake|
 .. -----------------
 
-..  LocalWords:  cmake PROMOD
+..  LocalWords:  cmake PROMOD CMakeLists txt promod unittest codetest xml py
+..  LocalWords:  libexec