Merge pull request #14828 from hazzlim/add-cmake-supports-psa-tests ...

CMake: Add CMake to mbed-psa greentea tests

CMake: Require TEST_SOURCES in greentea CMake file ...

Assumption that greentea test file is always named main.cpp is
incorrect. Updated mbed_greentea_add_test() macro to make TEST_SOURCES
parameter compulsory, which is used to specify greentea test
file(s). This allows tests to use C, or have a different name.
Therefore also updated all pre-existing greentea test CMake files to
explicity add main.cpp to TEST_SOURCES.

CMake: unit-tests: Make events UNITTESTS only depend on headers it uses ...

Previously the events unit tests depended on `mbed-headers`, which
is a collection of all available headers in mbed-os. To make it easier
to separate the library, only depend on the headers we're using.

CMake: Only build unit tests if Mbed OS is the current project ...

Typically when adding a unit test directory to a CMake project a check
will be used to ensure the subdirectory is added only if the following
are true:

* The BUILD_TESTING option is set to ON.
* The current CMake project is the top-level project.

The reason being, if a downstream project includes our project they
generally don't want to build our unit tests.

In mbed-os, we do correctly specify the above condition before adding
the central UNITTEST subdirectory, which fetches googletest and adds the
"stub" libraries the unit tests depend on. However, we only check if
CMAKE_CROSSCOMPILING is OFF (or undefined) before actually adding the
unit tests. This mismatched logic would lead to unexpected build
failures in various scenarios. One likely case could be: a downstream
project including mbed-os happens to set CMAKE_CROSSCOMPILING to
OFF/undefined for any reason (possibly to build its own unit tests).
mbed-os would go ahead and attempt to build its tests without fetching
googletest or adding the required stub targets.

To fix the issue replace the check for CMAKE_CROSSCOMPILING in the unit
tests with the same BUILD_TESTING idiom we use for adding the central
UNITTESTS subdirectory.

CMake: Remove all unittest.cmake script from test suite ...

- Remove redundant cmake script as already added the CMake configuration file
- Remove redundant empty_baseline as it is no longer needed with the help of CMake configuration file

CMake: Move CMAKE_CROSSCOMPILING check inside library CMake

CMake: Refactor event unittest cmake ...

- Added CMake configuration file into events unittests

CMake: Add add_subdirectory of unittests ...

- add every libraries unittest directory into respective CMake
  which allows to include unittest source into build based on
  MBED_BUILD_UNITTESTS flag

Update UserAllocatedEvent.h

Update Event.h

Update equeue.h

Update EventQueue.h

Update equeue.h

Update README.md

Update README.md

Update README.md

extend the event generation int

bigger equeue generation size and only increment when needed ...

to mitigate against generation clash

Merge pull request #13975 from adbridge/eventq ...

Update EventQueue API to use chrono times

Remove trailing space

Tweak events API update and update Greentea tests accordingly

CMake: rename greentea test macro

Merge pull request #14087 from adbridge/events ...

Update events period method to check for invalid values

Minor formatting tweak to fix file permissions

Revert "one final whitespace change!" ...

This reverts commit c9a3375.

one final whitespace change!

Further whitespace fixes

Fix whitespace to stop astyle complaining

Fix astyle issues

Remove unecessary namespace qualified ...

(Also minor whitespace correction)